audd-python: README — switch longpoll example to one-step form

Main longpoll example uses the new one-step entry point added in the SDK's most recent release. The 2-step derive_longpoll_category → longpoll(category) form stays documented under the 'Tokenless consumers' section, where it's the right tool: a server with the api_token derives the category and ships only the 9-char string to a browser/mobile/embedded client.

Author: AudD

README.md

@@ -249,9 +249,9 @@ If you can't expose a public callback URL, longpoll instead. AudD still requires
 The poll handle exposes three iterators — `matches`, `notifications`, `errors` — populated by a background thread (or task, in async). Use it as a context manager for clean shutdown:
 
 ```python
-category = audd.streams.derive_longpoll_category(radio_id=42)
+radio_id = 1  # any integer you choose — your handle for this stream
 
-with audd.streams.longpoll(category, timeout=30) as poll:
+with audd.streams.longpoll(radio_id=radio_id, timeout=30) as poll:
     for match in poll.matches:
         print(match.song.artist, "—", match.song.title)
 ```