"Decorated property not supported"

This is kind of unfortunate. Repro:

```
def noop(arg):
    def outer(func):
        def inner(*args, **kwds): return func(*args, **kwds)
    return outer

class C:
    @property  # E: Decorated property not supported
    @noop('hello')
    def foo(self):
        pass
```

I would like to at least have a way to claim that noop() returns a decorator that doesn't change the type.
