Update app.py

app.py

@@ -97,6 +97,9 @@ async def on_chat_start():
         service_context=service_context,
     )
 
+    msg.content = f"Processing `{file.name}` done. You can now ask questions!"
+    await msg.update()
+
     cl.user_session.set("query_engine", query_engine)