[DOC] Fix indent of set_trace_func document

Merged: https://github.com/ruby/ruby/pull/8364

vm_trace.c

@@ -510,62 +510,64 @@ static void call_trace_func(rb_event_flag_t, VALUE data, VALUE self, ID id, VALU
 /* (2-1) set_trace_func (old API) */
 
 /*
- *  call-seq:
- *     set_trace_func(proc)    -> proc
- *     set_trace_func(nil)     -> nil
+ * call-seq:
+ *    set_trace_func(proc)    -> proc
+ *    set_trace_func(nil)     -> nil
  *
- *  Establishes _proc_ as the handler for tracing, or disables
- *  tracing if the parameter is +nil+.
+ * Establishes _proc_ as the handler for tracing, or disables
+ * tracing if the parameter is +nil+.
  *
- *  *Note:* this method is obsolete, please use TracePoint instead.
+ * *Note:* this method is obsolete, please use TracePoint instead.
  *
- *  _proc_ takes up to six parameters:
+ * _proc_ takes up to six parameters:
  *
- *  *	an event name
- *  *	a filename
- *  *	a line number
- *  *	an object id
- *  *	a binding
- *  *	the name of a class
+ * * an event name
+ * * a filename
+ * * a line number
+ * * an object id
+ * * a binding
+ * * the name of a class
  *
- *  _proc_ is invoked whenever an event occurs.
+ * _proc_ is invoked whenever an event occurs.
  *
- *  Events are:
+ * Events are:
  *
- *  +c-call+:: call a C-language routine
- *  +c-return+:: return from a C-language routine
- *  +call+:: call a Ruby method
- *  +class+:: start a class or module definition
- *  +end+:: finish a class or module definition
- *  +line+:: execute code on a new line
- *  +raise+:: raise an exception
- *  +return+:: return from a Ruby method
+ * +c-call+:: call a C-language routine
+ * +c-return+:: return from a C-language routine
+ * +call+:: call a Ruby method
+ * +class+:: start a class or module definition
+ * +end+:: finish a class or module definition
+ * +line+:: execute code on a new line
+ * +raise+:: raise an exception
+ * +return+:: return from a Ruby method
  *
- *  Tracing is disabled within the context of _proc_.
+ * Tracing is disabled within the context of _proc_.
  *
- *      class Test
- *	def test
- *	  a = 1
- *	  b = 2
- *	end
- *      end
+ *   class Test
+ *     def test
+ *       a = 1
+ *       b = 2
+ *     end
+ *   end
  *
- *      set_trace_func proc { |event, file, line, id, binding, classname|
- *	   printf "%8s %s:%-2d %10s %8s\n", event, file, line, id, classname
- *      }
- *      t = Test.new
- *      t.test
+ *   set_trace_func proc { |event, file, line, id, binding, classname|
+ *      printf "%8s %s:%-2d %10s %8s\n", event, file, line, id, classname
+ *   }
+ *   t = Test.new
+ *   t.test
  *
- *	  line prog.rb:11               false
- *      c-call prog.rb:11        new    Class
- *      c-call prog.rb:11 initialize   Object
- *    c-return prog.rb:11 initialize   Object
- *    c-return prog.rb:11        new    Class
- *	  line prog.rb:12               false
- *  	  call prog.rb:2        test     Test
- *	  line prog.rb:3        test     Test
- *	  line prog.rb:4        test     Test
- *      return prog.rb:4        test     Test
+ * Produces:
+ *
+ *       line prog.rb:11               false
+ *     c-call prog.rb:11        new    Class
+ *     c-call prog.rb:11 initialize   Object
+ *   c-return prog.rb:11 initialize   Object
+ *   c-return prog.rb:11        new    Class
+ *       line prog.rb:12               false
+ *       call prog.rb:2        test     Test
+ *       line prog.rb:3        test     Test
+ *       line prog.rb:4        test     Test
+ *     return prog.rb:4        test     Test
  *
  * Note that for +c-call+ and +c-return+ events, the binding returned is the
  * binding of the nearest Ruby method calling the C method, since C methods