Fix typos in docs, error messages and comments

[jianghuyiyuan]

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📚 Documentation preview 📚: https://cpython-previews--122502.org.readthedocs.build/

[ghost]

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[bedevere-app]

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If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

[erlend-aasland]

Thanks, but I think we can manage with these minor inconsistencies in the comments.

[AlexWaygood]

This PR touches six files. Of the six files touched, three of the files are docs files, in which the PR fixes grammatical errors in the docs, and in a fourth file the PR fixes a spelling error in a message that could be shown to a user.

I agree with @erlend-aasland that we don't want to encourage PRs that only fix typos in comments, but — despite its current title — that's not what this PR does. I think overall the changes this PR makes are valuable.

[miss-islington-app]

Thanks @jianghuyiyuan for the PR, and @AlexWaygood for merging it 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @jianghuyiyuan and @AlexWaygood, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 46f5a4f9e1781ad8d60eb53bbaf6cd8534a286cd 3.13

[miss-islington-app]

Sorry, @jianghuyiyuan and @AlexWaygood, I could not cleanly backport this to 3.12 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 46f5a4f9e1781ad8d60eb53bbaf6cd8534a286cd 3.12

[erlend-aasland]

and in a fourth file the PR fixes a spelling error in a message that could be shown to a user

More specific a user who builds a debug build of CPython; the error message is guarded by the debug flag.

[picnixz]

Actually, we had a bunch of similar PRs that were accepted those past weeks (even when touching the C code) so I think we should have allowed this one as well: https://github.com/python/cpython/pulls?q=is%3Apr+author%3Axyb+sort%3Aupdated-desc (those are the PRs I rememebered)

[bedevere-app]

GH-122605 is a backport of this pull request to the 3.12 branch.

[bedevere-app]

GH-122606 is a backport of this pull request to the 3.13 branch.