Bumped version to 2.12.0. (starkware-libs#8068)

Stopped updating snap-refs - and only introducing top level. (starkwa…

…re-libs#8048)

Cherry picks (starkware-libs#8009)

Merge main into dev v2.12.0 (starkware-libs#7951)

Bumped version to 2.12.0-rc.0

Enabled efficient int-range.

Remove unused libfuncs. (starkware-libs#7488)

Bump version to 2.12.0-dev.0.

Fixed issue with sort instability of use statements. (starkware-libs#…

…7440)

Downgraded SmolStr lib. (starkware-libs#7405)