Adds missing __dir__ definitions (#8479)

stdlib/unittest/mock.pyi

@@ -121,6 +121,7 @@ class NonCallableMock(Base, Any):
     def __getattr__(self, name: str) -> Any: ...
     def __delattr__(self, name: str) -> None: ...
     def __setattr__(self, name: str, value: Any) -> None: ...
+    def __dir__(self) -> list[str]: ...
     if sys.version_info >= (3, 8):
         def _calls_repr(self, prefix: str = ...) -> str: ...
         def assert_called_with(self, *args: Any, **kwargs: Any) -> None: ...