Give up on being restrictive with visitor

Author: rmosolgo

lib/graphql/language/visitor.rb

@@ -147,7 +147,6 @@ def on_node_with_modifications(node, parent)
           new_parent = new_parent && new_parent.delete_child(node)
           return nil, new_parent
         else
-          # TODO: be less lax here
           # The user-provided hook didn't make any modifications.
           # In fact, the hook might have returned who-knows-what, so
           # ignore the return value and use the original values.