Document about base64 at Ruby 3.4

doc/maintainers.md

@@ -77,11 +77,6 @@ have commit right, others don't.
 * https://github.com/ruby/abbrev
 * https://rubygems.org/gems/abbrev
 
-#### lib/base64.rb
-* Yusuke Endoh (mame)
-* https://github.com/ruby/base64
-* https://rubygems.org/gems/base64
-
 #### lib/benchmark.rb
 * *unmaintained*
 * https://github.com/ruby/benchmark
@@ -483,6 +478,9 @@ have commit right, others don't.
 #### lib/getoptlong.rb
 * https://github.com/ruby/getoptlong
 
+#### lib/base64.rb
+* https://github.com/ruby/base64
+
 ## Platform Maintainers
 ### mswin64 (Microsoft Windows)
 * NAKAMURA Usaku (usa)

doc/standard_library.rdoc

@@ -34,7 +34,6 @@ Socket:: Access underlying OS socket implementations
 == Libraries
 
 Abbrev:: Calculates a set of unique abbreviations for a given set of strings
-Base64:: Support for encoding and decoding binary data using a Base64 representation
 Benchmark:: Provides methods to measure and report the time used to execute code
 Bundler:: Manage your Ruby application's gem dependencies
 CGI:: Support for the Common Gateway Interface protocol
@@ -130,3 +129,4 @@ DEBUGGER__:: Debugging functionality for Ruby
 Racc:: A LALR(1) parser generator written in Ruby.
 Mutex_m:: Mixin to extend objects to be handled like a Mutex
 GetoptLong:: Parse command line options similar to the GNU C getopt_long()
+Base64:: Support for encoding and decoding binary data using a Base64 representation