Add type hints to SimpleCustomFilter

Author: vehlwn

telebot/asyncio_filters.py

@@ -27,7 +27,7 @@ def check(self, message):
 
     key: str = None
 
-    async def check(self, message):
+    async def check(self, message: types.Message) -> bool:
         """
         Perform a check.
         """