readline.c: improve docs
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65040 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
readline.c: improve docs
Readline.completion_quote_character; enable link to method.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65040 b2dd03c8-39d4-4d8f-98ff-823fe69b080e