Fix #795: Incorrect typing with async decorators

[janek-cosmose]

No description provided.

[janek-cosmose]

Fixes #795

[janek-cosmose]

Tested with mypy 1.8.2 on dramatiq project and on sample file:

import dramatiq


@dramatiq.actor
async def foo() -> None:
    pass


@dramatiq.actor()
async def foo1() -> None:
    pass


@dramatiq.actor
def foo2() -> None:
    pass


@dramatiq.actor()
def foo3() -> None:
    pass