nightly#143 adaptations for nightly-2025-12-14

Stream: nightly-testing

[Kim Morrison]

chore: adaptations for nightly-2025-12-14 nightly#143 Please review this PR. At the next toolchain release this diff will land in 'master'.

[Kim Morrison]

Straightforward, removing a few adaptation notes about changes in behaviour in grind, and removing one grind annotation that is no longer needed now the grind has special handling for Int.sign.