Simplify example code in asyncio docs

[eumiro]

Replace {time.strftime('%X')} with {time:%X} in the asyncio-task docs to lower the complexity of the code that is not the main topic of the docs and not stealing the attention of the reader.

---

📚 Documentation preview 📚: https://cpython-previews--131209.org.readthedocs.build/

[hauntsaninja]

Thanks. I like the intention, but the time symbol is introduced with import time — we should make sure that a user could fairly easily run the code and produce the expected output themselves.

[eumiro]

You're right, @hauntsaninja . This really stole my attention.