update document to follow MatchData#inspect implementation.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12589 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

re.c

@@ -2313,7 +2313,7 @@ match_setter(VALUE val)
  *  <code>MatchData</code> object.
  *
  *     /c(.)t/ =~ 'cat'       #=> 0
- *     Regexp.last_match      #=> #<MatchData:0x401b3d30>
+ *     Regexp.last_match      #=> #<MatchData "cat" "a">
  *     Regexp.last_match(0)   #=> "cat"
  *     Regexp.last_match(1)   #=> "a"
  *     Regexp.last_match(2)   #=> nil

string.c

@@ -1423,7 +1423,7 @@ static VALUE get_pat(VALUE, int);
  *  parameter is present, it specifies the position in the string to begin the
  *  search.
  *     
- *     'hello'.match('(.)\1')      #=> #<MatchData:0x401b3d30>
+ *     'hello'.match('(.)\1')      #=> #<MatchData "ll" "l">
  *     'hello'.match('(.)\1')[0]   #=> "ll"
  *     'hello'.match(/(.)\1/)[0]   #=> "ll"
  *     'hello'.match('xx')         #=> nil