specify failure reason

Author: tdub0

Lib/test/test_types.py

@@ -602,7 +602,8 @@ def test_slot_wrapper_types(self):
         self.assertIsInstance(object.__lt__, types.WrapperDescriptorType)
         self.assertIsInstance(int.__lt__, types.WrapperDescriptorType)
 
-    # TODO: RUSTPYTHON
+    # TODO: No signature found in builtin method __get__ of 'method_descriptor'
+    # objects so ValueError is raised
     @unittest.expectedFailure
     def test_dunder_get_signature(self):
         sig = inspect.signature(object.__init__.__get__)