fix #1849 (closure_subset -> closureS)

[t6s]

Motivation for this change

• fix naming glitch at closure_subset #1849
• add interiorS

Checklist

• added corresponding entries in CHANGELOG_UNRELEASED.md

• added corresponding documentation in the headers

Reference: How to document

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• PRs with disorganized commits are very likely to be squash-rebased.

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[affeldt-aist]

A rebase and we're done! Thanks for noticing the naming issue.

[t6s]

rebased

[affeldt-aist]

it looks like use is not supported by Coq 8.20:

#[deprecated(since="mathcomp-analysis 1.16.0", use=closureS)]
Definition closure_subset := closureS.

you can use note