Fix incorrect return annotation in asyncio.lock (#2155)

NoReturn should be used only when the function never returns. In this case, the awaitable returns None if releasing the lock succeeds, so `Awaitable[None]` is right.

Noticed this while reviewing python/typeshed#7676

Author: JelleZijlstra

redis/asyncio/lock.py

@@ -3,7 +3,7 @@
 import threading
 import uuid
 from types import SimpleNamespace
-from typing import TYPE_CHECKING, Awaitable, NoReturn, Optional, Union
+from typing import TYPE_CHECKING, Awaitable, Optional, Union
 
 from redis.exceptions import LockError, LockNotOwnedError
 
@@ -243,15 +243,15 @@ async def owned(self) -> bool:
             stored_token = encoder.encode(stored_token)
         return self.local.token is not None and stored_token == self.local.token
 
-    def release(self) -> Awaitable[NoReturn]:
+    def release(self) -> Awaitable[None]:
         """Releases the already acquired lock"""
         expected_token = self.local.token
         if expected_token is None:
             raise LockError("Cannot release an unlocked lock")
         self.local.token = None
         return self.do_release(expected_token)
 
-    async def do_release(self, expected_token: bytes):
+    async def do_release(self, expected_token: bytes) -> None:
         if not bool(
             await self.lua_release(
                 keys=[self.name], args=[expected_token], client=self.redis