fix(typing): mark after as optional

Co-authored-by: Dorukyum <[email protected]>
Signed-off-by: Krutyi-4el <[email protected]>

discord/voice_client.py

@@ -647,7 +647,7 @@ def play(
         self,
         source: AudioSource,
         *,
-        after: Callable[[Exception | None], Any] = None,
+        after: Callable[[Exception | None], Any] | None = None,
         wait_finish: bool = False,
     ) -> None | asyncio.Future:
         """Plays an :class:`AudioSource`.