Fix return type docstring in Message.delete() (#186)

Author: RimMirK

pyrogram/types/messages_and_media/message.py

@@ -5436,7 +5436,7 @@ async def delete(self, revoke: bool = True):
                 Defaults to True.
 
         Returns:
-            True on success, False otherwise.
+            ``int`` – Amount of affected messages.
 
         Raises:
             RPCError: In case of a Telegram RPC error.