Rollup merge of #42496 - Razaekel:feature/integer_max-min, r=BurntSushi

Add max and min to Ord

Pursuant to issue #25663, this PR adds max and min methods with default implementations to std::cmp::Ord. It also modifies std::cmp::max|min to internally alias to Ord::max|min, so that any overrides of the default implementations are automatically used by std::cmp::max|min.

Closes #25663