parse.y: fix op_assign type
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52318 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
parse.y: fix op_assign type
already an ID since r52284. [Feature #11537]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52318 b2dd03c8-39d4-4d8f-98ff-823fe69b080e