enumerator.c: append_method

* enumerator.c (append_method): extract from inspect_enumerator().

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40804 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
enumerator.c: use VALUE

* enumerator.c (inspect_enumerator): use VALUE instead of mere char*
  by using rb_sprintf() and rb_id2str().

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40805 b2dd03c8-39d4-4d8f-98ff-823fe69b080e