Fix type hints on GuildChannel.set_permissions

discord/abc.py

@@ -904,7 +904,7 @@ class GuildChannel:
         target: Union[Member, Role],
         *,
         reason: Optional[str] = ...,
-        **permissions: bool,
+        **permissions: Optional[bool],
     ) -> None:
         ...
 
@@ -914,7 +914,7 @@ class GuildChannel:
         *,
         overwrite: Any = _undefined,
         reason: Optional[str] = None,
-        **permissions: bool,
+        **permissions: Optional[bool],
     ) -> None:
         r"""|coro|