Update message.py: add BinaryIO return-type hint in download() (#117)

Author: anonymousx97

pyrogram/types/messages_and_media/message.py

@@ -5294,7 +5294,7 @@ async def download(
         block: bool = True,
         progress: Callable = None,
         progress_args: tuple = ()
-    ) -> str:
+    ) -> Union[str, BinaryIO]:
         """Bound method *download* of :obj:`~pyrogram.types.Message`.
 
         Use as a shortcut for: