[DOC] Fix grammar errors, typos, and improve readability of string.rb

Because this file's comments have one extra space after the `#` sign,
almost every line is updated. IMO, it's better to address this issue
in one go.

Co-authored-by: Jeremy Evans <code@jeremyevans.net>

string.rb

@@ -17,11 +17,11 @@
 # Some +String+ methods modify +self+.
 # Typically, a method whose name ends with <tt>!</tt> modifies +self+
 # and returns +self+;
-#  often a similarly named method (without the <tt>!</tt>)
+# often, a similarly named method (without the <tt>!</tt>)
 # returns a new string.
 #
-#  In general, if there exist both bang and non-bang version of method,
+# In general, if both bang and non-bang versions of a method exist,
-#  the bang! mutates and the non-bang! does not.
+# the bang method mutates and the non-bang method does not.
 # However, a method without a bang can also mutate, such as String#replace.
 #
 # == Substitution Methods
@@ -37,16 +37,16 @@
 #
 # Each of these methods takes:
 #
-#  - A first argument, +pattern+ (string or regexp),
+# - A first argument, +pattern+ (String or Regexp),
 #   that specifies the substring(s) to be replaced.
 #
-#  - Either of these:
+# - Either of the following:
 #
-#    - A second argument, +replacement+ (string or hash),
+#   - A second argument, +replacement+ (String or Hash),
 #     that determines the replacing string.
 #   - A block that will determine the replacing string.
 #
-#  The examples in this section mostly use methods String#sub and String#gsub;
+# The examples in this section mostly use the String#sub and String#gsub methods;
 # the principles illustrated apply to all four substitution methods.
 #
 # <b>Argument +pattern+</b>
@@ -62,26 +62,26 @@
 #   'THX1138'.gsub(/\d+/, '00') # => "THX00"
 #
 # When +pattern+ is a string, all its characters are treated
-#  as ordinary characters (not as regexp special characters):
+# as ordinary characters (not as Regexp special characters):
 #
 #   'THX1138'.gsub('\d+', '00') # => "THX1138"
 #
 # <b>+String+ +replacement+</b>
 #
-#  If +replacement+ is a string, that string will determine
+# If +replacement+ is a string, that string determines
-#  the replacing string that is to be substituted for the matched text.
+# the replacing string that is substituted for the matched text.
 #
 # Each of the examples above uses a simple string as the replacing string.
 #
 # +String+ +replacement+ may contain back-references to the pattern's captures:
 #
-#  - <tt>\n</tt> (_n_ a non-negative integer) refers to <tt>$n</tt>.
+# - <tt>\n</tt> (_n_ is a non-negative integer) refers to <tt>$n</tt>.
 # - <tt>\k<name></tt> refers to the named capture +name+.
 #
 # See Regexp for details.
 #
 # Note that within the string +replacement+, a character combination
-#  such as <tt>$&</tt> is treated as ordinary text, and not as
+# such as <tt>$&</tt> is treated as ordinary text, not as
 # a special match variable.
 # However, you may refer to some special match variables using these
 # combinations:
@@ -89,11 +89,11 @@
 # - <tt>\&</tt> and <tt>\0</tt> correspond to <tt>$&</tt>,
 #   which contains the complete matched text.
 # - <tt>\'</tt> corresponds to <tt>$'</tt>,
-#    which contains string after match.
+#   which contains the string after the match.
 # - <tt>\`</tt> corresponds to <tt>$`</tt>,
-#    which contains string before match.
+#   which contains the string before the match.
 # - <tt>\\+</tt> corresponds to <tt>$+</tt>,
-#    which contains last capture group.
+#   which contains the last capture group.
 #
 # See Regexp for details.
 #
@@ -108,16 +108,16 @@
 # <tt>"..\\\\&.."</tt>.
 #
 # If you want to write a non-back-reference string <tt>\&</tt> in
-#  +replacement+, you need first to escape the backslash to prevent
+# +replacement+, you need to first escape the backslash to prevent
 # this method from interpreting it as a back-reference, and then you
 # need to escape the backslashes again to prevent a string literal from
 # consuming them: <tt>"..\\\\\\\\&.."</tt>.
 #
-#  You may want to use the block form to avoid a lot of backslashes.
+# You may want to use the block form to avoid excessive backslashes.
 #
 # <b>\Hash +replacement+</b>
 #
-#  If argument +replacement+ is a hash, and +pattern+ matches one of its keys,
+# If the argument +replacement+ is a hash, and +pattern+ matches one of its keys,
 # the replacing string is the value for that key:
 #
 #   h = {'foo' => 'bar', 'baz' => 'bat'}
@@ -141,7 +141,7 @@
 #
 # == Whitespace in Strings
 #
-#  In class +String+, _whitespace_ is defined as a contiguous sequence of characters
+# In the class +String+, _whitespace_ is defined as a contiguous sequence of characters
 # consisting of any mixture of the following:
 #
 # - NL (null): <tt>"\x00"</tt>, <tt>"\u0000"</tt>.
@@ -153,37 +153,37 @@
 # - SP (space): <tt>"\x20"</tt>, <tt>" "</tt>.
 #
 #
-#  Whitespace is relevant for these methods:
+# Whitespace is relevant for the following methods:
 #
-#  - #lstrip, #lstrip!: strip leading whitespace.
+# - #lstrip, #lstrip!: Strip leading whitespace.
-#  - #rstrip, #rstrip!: strip trailing whitespace.
+# - #rstrip, #rstrip!: Strip trailing whitespace.
-#  - #strip, #strip!: strip leading and trailing whitespace.
+# - #strip, #strip!: Strip leading and trailing whitespace.
 #
 # == +String+ Slices
 #
-#  A _slice_ of a string is a substring that is selected by certain criteria.
+# A _slice_ of a string is a substring selected by certain criteria.
 #
-#  These instance methods make use of slicing:
+# These instance methods utilize slicing:
 #
-#  - String#[] (aliased as String#slice): returns a slice copied from +self+.
+# - String#[] (aliased as String#slice): Returns a slice copied from +self+.
-#  - String#[]=: returns a copy of +self+ with a slice replaced.
+# - String#[]=: Mutates +self+ with the slice replaced.
-#  - String#slice!: returns +self+ with a slice removed.
+# - String#slice!: Mutates +self+ with the slice removed and returns the removed slice.
 #
 # Each of the above methods takes arguments that determine the slice
 # to be copied or replaced.
 #
 # The arguments have several forms.
-#  For string +string+,  the forms are:
+# For a string +string+, the forms are:
 #
-#  - <tt>string[index]</tt>.
+# - <tt>string[index]</tt>
-#  - <tt>string[start, length]</tt>.
+# - <tt>string[start, length]</tt>
-#  - <tt>string[range]</tt>.
+# - <tt>string[range]</tt>
-#  - <tt>string[regexp, capture = 0]</tt>.
+# - <tt>string[regexp, capture = 0]</tt>
-#  - <tt>string[substring]</tt>.
+# - <tt>string[substring]</tt>
 #
 # <b><tt>string[index]</tt></b>
 #
-#  When non-negative integer argument +index+ is given,
+# When a non-negative integer argument +index+ is given,
 # the slice is the 1-character substring found in +self+ at character offset +index+:
 #
 #   'bar'[0]      # => "b"
@@ -192,7 +192,7 @@
 #   'тест'[2]     # => "с"
 #   'こんにちは'[4] # => "は"
 #
-#  When negative integer +index+ is given,
+# When a negative integer +index+ is given,
 # the slice begins at the offset given by counting backward from the end of +self+:
 #
 #   'bar'[-3]      # => "b"
@@ -215,30 +215,30 @@
 #   # Start out of range.
 #   'foo'[4, 2]      # => nil
 #
-#  Special case: if +start+ is equal to the length of +self+,
+# Special case: if +start+ equals the length of +self+,
 # the slice is a new empty string:
 #
 #   'foo'[3, 2]    # => ""
 #   'foo'[3, 200]  # => ""
 #
-#  When negative +start+ and non-negative +length+ are given,
+# When a negative +start+ and non-negative +length+ are given,
-#  the slice beginning is determined by counting backward from the end of +self+,
+# the slice begins by counting backward from the end of +self+,
-#  and the slice continues for +length+ characters, if available:
+# and continues for +length+ characters, if available:
 #
 #   'foo'[-2, 2]     # => "oo"
 #   'foo'[-2, 200]   # => "oo"
 #   # Start out of range.
 #   'foo'[-4, 2]     # => nil
 #
-#  When negative +length+ is given, there is no slice:
+# When a negative +length+ is given, there is no slice:
 #
 #   'foo'[1, -1]   # => nil
 #   'foo'[-2, -1]  # => nil
 #
 # <b><tt>string[range]</tt></b>
 #
-#  When Range argument +range+ is given,
+# When a Range argument +range+ is given,
-#  creates a substring of +string+ using the indices in +range+.
+# it creates a substring of +string+ using the indices in +range+.
 # The slice is then determined as above:
 #
 #   'foo'[0..1]     # => "fo"
@@ -277,10 +277,10 @@
 #   s[/[aeiou](.)\1/]        # => "ell"
 #   s[/[aeiou](.)\1/, 0]     # => "ell"
 #
-#  If argument +capture+ is given and not <tt>0</tt>,
+# If the argument +capture+ is provided and not <tt>0</tt>,
-#  it should be either an capture group index (integer)
+# it should be either a capture group index (integer)
-#  or a capture group name (string or symbol);
+# or a capture group name (String or Symbol);
-#  the slice is the specified capture (see Regexp@Groups+and+Captures):
+# the slice is the specified capture (see Regexp@Groups and Captures):
 #
 #   s = 'hello there'
 #   s[/[aeiou](.)\1/, 1] # => "l"
@@ -293,7 +293,7 @@
 # <b><tt>string[substring]</tt></b>
 #
 # When the single +String+ argument +substring+ is given,
-#  returns the substring from +self+ if found, otherwise +nil+:
+# it returns the substring from +self+ if found, otherwise +nil+:
 #
 #   'foo'['oo'] # => "oo"
 #   'foo'['xx'] # => nil
@@ -302,8 +302,8 @@
 #
 # First, what's elsewhere. \Class +String+:
 #
-#  - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
+# - Inherits from the {Object class}[rdoc-ref:Object@What-27s+Here].
-#  - Includes {module Comparable}[rdoc-ref:Comparable@What-27s+Here].
+# - Includes the {Comparable module}[rdoc-ref:Comparable@What-27s+Here].
 #
 # Here, class +String+ provides methods that are useful for:
 #
@@ -323,11 +323,11 @@
 #
 # === Methods for a Frozen/Unfrozen String
 #
-#  - #+@: Returns a string that is not frozen: +self+, if not frozen;
+# - #+@: Returns a string that is not frozen: +self+ if not frozen;
 #   +self.dup+ otherwise.
-#  - #-@ (aliased as #dedup): Returns a string that is frozen: +self+, if already frozen;
+# - #-@ (aliased as #dedup): Returns a string that is frozen: +self+ if already frozen;
 #   +self.freeze+ otherwise.
-#  - #freeze: Freezes +self+, if not already frozen; returns +self+.
+# - #freeze: Freezes +self+ if not already frozen; returns +self+.
 #
 # === Methods for Querying
 #
@@ -382,7 +382,7 @@
 #
 # _Insertion_
 #
-#  - #insert: Returns +self+ with a given string inserted at a given offset.
+# - #insert: Returns +self+ with a given string inserted at a specified offset.
 # - #<<: Returns +self+ concatenated with a given string or integer.
 # - #append_as_bytes: Returns +self+ concatenated with strings without performing any
 #   encoding validation or conversion.
@@ -414,7 +414,7 @@
 #
 # _Encoding_
 #
-#  - #encode!: Returns +self+ with all characters transcoded from one given encoding into another.
+# - #encode!: Returns +self+ with all characters transcoded from one encoding to another.
 # - #unicode_normalize!: Unicode-normalizes +self+; returns +self+.
 # - #scrub!: Replaces each invalid byte with a given character; returns +self+.
 # - #force_encoding: Changes the encoding to a given encoding; returns +self+.
@@ -428,7 +428,7 @@
 # - #lstrip!: Removes leading whitespace; returns +self+ if any changes, +nil+ otherwise.
 # - #rstrip!: Removes trailing whitespace; returns +self+ if any changes, +nil+ otherwise.
 # - #strip!: Removes leading and trailing whitespace; returns +self+ if any changes, +nil+ otherwise.
-#  - #chomp!: Removes trailing record separator, if found; returns +self+ if any changes, +nil+ otherwise.
+# - #chomp!: Removes the trailing record separator, if found; returns +self+ if any changes, +nil+ otherwise.
 # - #chop!: Removes trailing newline characters if found; otherwise removes the last character;
 #   returns +self+ if any changes, +nil+ otherwise.
 #
@@ -439,9 +439,9 @@
 #
 # _Extension_
 #
-#  - #*: Returns the concatenation of multiple copies of +self+,
+# - #*: Returns the concatenation of multiple copies of +self+.
 # - #+: Returns the concatenation of +self+ and a given other string.
-#  - #center: Returns a copy of +self+ centered between pad substring.
+# - #center: Returns a copy of +self+ centered between pad substrings.
 # - #concat: Returns the concatenation of +self+ with given other strings.
 # - #prepend: Returns the concatenation of a given other string with +self+.
 # - #ljust: Returns a copy of +self+ of a given length, right-padded with a given other string.
@@ -452,16 +452,16 @@
 # - #b: Returns a copy of +self+ with ASCII-8BIT encoding.
 # - #scrub: Returns a copy of +self+ with each invalid byte replaced with a given character.
 # - #unicode_normalize: Returns a copy of +self+ with each character Unicode-normalized.
-#  - #encode: Returns a copy of +self+ with all characters transcoded from one given encoding into another.
+# - #encode: Returns a copy of +self+ with all characters transcoded from one encoding to another.
 #
 # _Substitution_
 #
 # - #dump: Returns a copy of +self+ with all non-printing characters replaced by \xHH notation
 #   and all special characters escaped.
-#  - #undump: Returns a copy of +self+ with all <tt>\xNN</tt> notation replace by <tt>\uNNNN</tt> notation
+# - #undump: Returns a copy of +self+ with all <tt>\xNN</tt> notations replaced by <tt>\uNNNN</tt> notations
 #   and all escaped characters unescaped.
 # - #sub: Returns a copy of +self+ with the first substring matching a given pattern
-#    replaced with a given replacement string;.
+#   replaced with a given replacement string.
 # - #gsub: Returns a copy of +self+ with each substring that matches a given pattern
 #   replaced with a given replacement string.
 # - #succ (aliased as #next): Returns the string that is the successor to +self+.
@@ -470,7 +470,7 @@
 # - #tr_s: Returns a copy of +self+ with specified characters replaced with
 #   specified replacement characters,
 #   removing duplicates from the substrings that were modified.
-#  - #%: Returns the string resulting from formatting a given object into +self+
+# - #%: Returns the string resulting from formatting a given object into +self+.
 #
 # _Casing_
 #
@@ -483,7 +483,7 @@
 #
 # _Deletion_
 #
-#  - #delete: Returns a copy of +self+ with characters removed
+# - #delete: Returns a copy of +self+ with characters removed.
 # - #delete_prefix: Returns a copy of +self+ with a given prefix removed.
 # - #delete_suffix: Returns a copy of +self+ with a given suffix removed.
 # - #lstrip: Returns a copy of +self+ with leading whitespace removed.
@@ -492,7 +492,7 @@
 # - #chomp: Returns a copy of +self+ with a trailing record separator removed, if found.
 # - #chop: Returns a copy of +self+ with trailing newline characters or the last character removed.
 # - #squeeze: Returns a copy of +self+ with contiguous duplicate characters removed.
-#  - #[] (aliased as #slice): Returns a substring determined by a given index, start/length, or range, or string.
+# - #[] (aliased as #slice): Returns a substring determined by a given index, start/length, range, regexp, or string.
 # - #byteslice: Returns a substring determined by a given index, start/length, or range.
 # - #chr: Returns the first character.
 #
@@ -510,23 +510,23 @@
 # - #bytes: Returns an array of the bytes in +self+.
 # - #chars: Returns an array of the characters in +self+.
 # - #codepoints: Returns an array of the integer ordinals in +self+.
-#  - #getbyte: Returns an integer byte as determined by a given index.
+# - #getbyte: Returns the integer byte at the given index in +self+.
 # - #grapheme_clusters: Returns an array of the grapheme clusters in +self+.
 #
 # _Splitting_
 #
 # - #lines: Returns an array of the lines in +self+, as determined by a given record separator.
 # - #partition: Returns a 3-element array determined by the first substring that matches
-#    a given substring or regexp,
+#   a given substring or regexp.
 # - #rpartition: Returns a 3-element array determined by the last substring that matches
-#    a given substring or regexp,
+#   a given substring or regexp.
 # - #split: Returns an array of substrings determined by a given delimiter -- regexp or string --
-#    or, if a block given, passes those substrings to the block.
+#   or, if a block is given, passes those substrings to the block.
 #
 # _Matching_
 #
 # - #scan: Returns an array of substrings matching a given regexp or string, or,
-#    if a block given, passes each matching substring to the  block.
+#   if a block is given, passes each matching substring to the block.
 # - #unpack: Returns an array of substrings extracted from +self+ according to a given format.
 # - #unpack1: Returns the first substring extracted from +self+ according to a given format.
 #
@@ -540,7 +540,7 @@
 #
 # <em>Strings and Symbols</em>
 #
-#  - #inspect: Returns copy of +self+, enclosed in double-quotes, with special characters escaped.
+# - #inspect: Returns a copy of +self+, enclosed in double quotes, with special characters escaped.
 # - #intern (aliased as #to_sym): Returns the symbol corresponding to +self+.
 #
 # === Methods for Iterating