update function name as it not halt request actually

docs/sanic/blueprints.md

@@ -66,7 +66,7 @@ Using blueprints allows you to also register middleware globally.
 
 ```python
 @bp.middleware
-async def halt_request(request):
+async def print_on_request(request):
 	print("I am a spy")
 
 @bp.middleware('request')