Fix #795: Fix typing of actor decorator to work with async actors (#796)

* Fix #795: Incorrect typing with async decorators
* add contrubutor, ignore E704

Author: janek-cosmose

.flake8

@@ -2,7 +2,7 @@
 max-complexity = 20
 max-line-length = 120
 select = C,E,F,W,B,B9,Q0
-ignore = E127,E203,E402,E501,F403,F811,W503,W504,B010,B020,B036,B905,B908
+ignore = E127,E203,E402,E501,E704,F403,F811,W503,W504,B010,B020,B036,B905,B908
 
 inline-quotes = double
 multiline-quotes = double

CONTRIBUTORS.md

@@ -75,3 +75,4 @@ of those changes to CLEARTYPE SRL.
 | [@gurelkaynak](https://gurel.kaynak.link)              | Gurel Kaynak           |
 | [@ksoviero-zengrc](https://github.com/ksoviero-zengrc) | Kevin Soviero          |
 | [@mikeroll](https://github.com/mikeroll)               | Mikhail Bulash         |
+| [@janek-cosmose](https://github.com/janek-cosmose)     | Jan Szejko             |

dramatiq/actor.py

@@ -27,6 +27,7 @@
     Generic,
     Optional,
     ParamSpec,
+    Protocol,
     TypeVar,
     Union,
     overload,
@@ -202,13 +203,28 @@ def __str__(self) -> str:
         return "Actor(%(actor_name)s)" % vars(self)
 
 
+class ActorDecorator(Protocol):
+    @overload
+    def __call__(self, fn: Callable[P, Awaitable[R]]) -> Actor[P, R]: ...
+
+    @overload
+    def __call__(self, fn: Callable[P, R]) -> Actor[P, R]: ...
+
+    def __call__(self, fn: Callable[P, Union[Awaitable[R], R]]) -> Actor[P, R]: ...
+
+
+@overload
+def actor(fn: Callable[P, Awaitable[R]], **kwargs) -> Actor[P, R]:
+    pass
+
+
 @overload
-def actor(fn: Callable[P, Union[Awaitable[R], R]], **kwargs) -> Actor[P, R]:
+def actor(fn: Callable[P, R], **kwargs) -> Actor[P, R]:
     pass
 
 
 @overload
-def actor(fn: None = None, **kwargs) -> Callable[[Callable[P, Union[Awaitable[R], R]]], Actor[P, R]]:
+def actor(fn: None = None, **kwargs) -> ActorDecorator:
     pass