The idea is that you run them on save, but you also run them again in CI in a "fail if you would've made changes" mode, so that if someone has their editor misc

The idea is that you run them on save, but you also run them again in CI in a "fail if you would've made changes" mode, so that if someone has their editor misconfigured or edits text with cat or whatever you still force them to run the formatter somehow before they can land their PR.