nightly#41 adaptations for nightly-2025-08-21

Stream: nightly-testing

[github mathlib4 bot]

chore: adaptations for nightly-2025-08-21 nightly#41 Please review this PR. At the next toolchain release this diff will land in 'master'.

[Kevin Buzzard]

Notes: (1) CI is failing on this (2) I often review and merge these things but these changes are mostly to CI and I am not competent to review them. Have they been piling up for a while? This is the first time I've looked at this channel for nearly two weeks.

[Kim Morrison]

We've stacked up three unmerged PRs, nightly#39, nightly#40, and nightly#41, which indeed are all failing CI. :-(

I haven't looked yet.

It's Saturday morning here; I may not get to it until Monday.

[Kim Morrison]

The CI failures were changes @Anne Baanen has been experimenting with directly on nightly-testing, I think fixed in d181915941abc8ca26f338353546e24e0b3cde82 and 1c3b9913c3557fee068e10b980a4e3c973e401af now.