UX: Improve revert label in post history modal (PR #10038)

This is a starter task I found in Meta: https://meta.discourse.org/t/can-the-revert-button-be-moved-to-the-left-of-the-revision-dialog/126926/7 Please evaluate.

GitHub

This looks good to me, thank you!

This pull request has been mentioned on Discourse Meta. There might be relevant details there:

https://meta.discourse.org/t/can-the-revert-button-be-moved-to-the-left-of-the-revision-dialog/126926/9