gh-91896: Fixup some docs issues following ByteString deprecation

[AlexWaygood]

• Get the doctests for collections.abc working again (see https://github.com/python/cpython/actions/runs/4957850824/jobs/8870015699 as an example failure). It was broken by gh-91896: Improve visibility of ByteString deprecation warnings #104294
• Explicitly note in whatsnew that typing.ByteString now causes DeprecationWarnings, as well as collections.abc.ByteString.

• Issue: Deprecate and schedule removal of collections.abc.ByteString and typing.ByteString #91896

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📚 Documentation preview 📚: https://cpython-previews--104422.org.readthedocs.build/

[JelleZijlstra]

I'd like to get this merged so we can get CI green, but we should consider whether the import * case is important enough to drop the warning. This would be annoying:

% ./python.exe -Werr Python 3.12.0a7+ (heads/tvobject-dirty:bc3757969b, May 12 2023, 06:50:26) [Clang 14.0.0 (clang-1400.0.29.202)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> from typing import * Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/Users/jelle/py/cpython/Lib/typing.py", line 3328, in __getattr__ warnings._deprecated("typing.ByteString", remove=(3, 14)) File "/Users/jelle/py/cpython/Lib/warnings.py", line 529, in _deprecated warn(msg, DeprecationWarning, stacklevel=3) DeprecationWarning: 'typing.ByteString' is deprecated and slated for removal in Python 3.14 >>>