fix #1843

[affeldt-aist]

Motivation for this change

fix #1843

@holgerthies -> we discussed renaming on the closed_comp lemma recently, eventually I didn't use the name we though of at the time, what do you think? (in MathComp, when the predicate is unary, the order is reversed on purpose @CohenCyril )

Checklist

• added corresponding entries in CHANGELOG_UNRELEASED.md

- [ ] added corresponding documentation in the headers

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[holgerthies]

I think the lemma names are more accurate now.