gh-96471: Correct docs for queue shutdown raises

[EpicWink]

• Remove "raises ShutDown" from Queue.join() and Queue.task_done() documentation (including doc-string)
• Clarify Queue.shutdown() behaviour (it doesn't raise itself, but causes other methods to raise)
• Add that Queue.task_done() is called by Queue.shutdown(immediate=True) for each item in the queue

Caused by: #104750

• Issue: Queue shutdown #96471

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📚 Documentation preview 📚: https://cpython-previews--115838.org.readthedocs.build/

[gvanrossum]

Thanks! Two nits and then I'll merge this. (I feel bad that I didn't catch this in review.)

[gvanrossum]

Please fix the nits I called out.

[bedevere-app]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[EpicWink]

I have made the requested changes; please review again