gh-81520: Add documentatoion about unexpected os.path.ismount() behaviour

[bionade24]

2 PRs, one adds documentation about the false positives with btrfs subvolumes & the 2nd about adding the unexpected behaviour to the docstring, so that it also shows up in pydoc

• Issue: gh-81520

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📚 Documentation preview 📚: https://cpython-previews--136058.org.readthedocs.build/

[python-cla-bot[bot]]

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[bedevere-app[bot]]

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[Zheaoli]

To be honest, I'm not sure we need to clarify this for other similar fs like zfs.

[bionade24]

To be honest, I'm not sure we need to clarify this for other similar fs like zfs.

What do you want to tell? This PR has nothing to do with ZFS and I don't know how os.path.ismount() behaves on it.

[bionade24]

Rebased it on main. Anything else that I need to do?

[ZeroIntensity]

FWIW, you don't need to force-push. We squash at the end anyway, and it just makes reviewing a little more difficult.

[miss-islington-app[bot]]

Thanks @bionade24 for the PR, and @ZeroIntensity for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14. 🐍🍒⛏🤖

[bedevere-app[bot]]

GH-136471 is a backport of this pull request to the 3.14 branch.

[bedevere-app[bot]]

GH-136473 is a backport of this pull request to the 3.13 branch.

[ZeroIntensity]

Congrats on your first contribution :)