Add extension example, replace input_hijack with chat_input_modifier (#3307)

extensions/api/streaming_api.py

@@ -2,12 +2,15 @@ import asyncio
 import json
 from threading import Thread
 
-from websockets.server import serve
-
-from extensions.api.util import build_parameters, try_start_cloudflared, with_api_lock
+from extensions.api.util import (
+    build_parameters,
+    try_start_cloudflared,
+    with_api_lock
+)
 from modules import shared
 from modules.chat import generate_chat_reply
 from modules.text_generation import generate_reply
+from websockets.server import serve
 
 PATH = '/api/v1/stream'