Fix printing object type definitions

Directives come after the implemented interfaces.

See
https://github.com/graphql/graphql-js/blob/360fa06e43fed32b63fba99b353515e7b56eee20/src/language/printer.js#L117-L129
for the canonical printer.

lib/graphql/language/printer.rb

@@ -154,8 +154,8 @@ def print_scalar_type_definition(scalar_type)
       def print_object_type_definition(object_type)
         out = print_description(object_type)
         out << "type #{object_type.name}"
-        out << print_directives(object_type.directives)
         out << " implements " << object_type.interfaces.map(&:name).join(", ") unless object_type.interfaces.empty?
+        out << print_directives(object_type.directives)
         out << print_field_definitions(object_type.fields)
       end