Rollup merge of #116661 - WaffleLapkin:make-reviews-change-pr-state, r=Mark-Simulacrum

Make "request changes" reviews apply `S-waiting-on-author`

This makes it so **assignee** requesting changes on a PR via GitHub UI adds https://github.com/rust-lang/rust/labels/S-waiting-on-author and removes https://github.com/rust-lang/rust/labels/S-waiting-on-review.

cc `@compiler-errors` :3

Author: GuillaumeGomez