-> rm | delete 'nats: connection is closed' msg for fut.cancel to ensure backward compatibility

Author: raprek

nats/aio/client.py

@@ -689,7 +689,7 @@ async def _close(self, status: int, do_cbs: bool = True) -> None:
             # so cancel them here to unblock them.
             if sub._pending_next_msgs_calls:
                 for fut in sub._pending_next_msgs_calls.values():
-                    fut.cancel("nats: connection is closed")
+                    fut.cancel()
                 sub._pending_next_msgs_calls.clear()
         self._subs.clear()