nightly#169 adaptations for nightly-2026-02-01

Stream: nightly-testing

[github mathlib4 bot]

chore: adaptations for nightly-2026-02-01 nightly#169

Please review this PR. At the next toolchain release this diff will land in 'master'.

[Johan Commelin]

I've merged this one.

It adds noncomputable in ~50 places. This is part of an effort to make noncomputable have more precise semantics and play well with the module system.

Also, a few adaptation notes were added together with a setting that allows for changing some reducibility settings locally, post-hoc.