Comment for usage of graphql_name

Co-authored-by: Robert Mosolgo <rmosolgo@github.com>

Author: grcooper

lib/graphql/schema.rb

@@ -1117,6 +1117,8 @@ def possible_types(type = nil, context = GraphQL::Query::NullContext)
               next true unless type.kind.interface?
               next true unless possible_type.kind.object?
 
+              # Use `.graphql_name` comparison to match legacy vs class-based types. 
+              # When we don't need to support legacy `.define` types, use `.include?(type)` instead.
               possible_type.interfaces(context).any? { |interface| interface.graphql_name == type.graphql_name }
             end if stored_possible_types
             visible_possible_types ||