Regression: Cannot combine @property decorator with @abstractclassmethod #7134

This commit changed the definition of abstractclassmethod and abstractstaticmethod in a way that makes them no longer callable. That means they cannot be used with other decorators (like property) that require a callable.

The following previously type checked without errors, but it no longer works.

    @property
    @abc.abstractclassmethod
    def foo(self) -> str: ...

The new declaration of abstractclassmethod and abstractstaticmethod also completely obscure the signature of the function they're decorating, which is a big problem for type checking (and completion suggestions, etc.).

I recommend reverting the change for abstractclassmethod and abstractstaticmethod. If there is a compelling reason to wrap these in a class, then the class should be parameterized with a ParamSpec and should include a __call__ method so it is still callable. @srittau, do you have a preference?

I won't be able to incorporate the latest typeshed stubs into pyright or pylance until this is addressed because this regression results in significant problems for internal Microsoft code bases.