Delete review comments while trying to edit them #3605

1. https://github.com/sindresorhus/refined-github/pull/3604/files
2. Go to edit a comment
3. Change your mind, you want to delete it
4. 5 clicks later, you can delete it

I think we can add a red-text "Delete" button to the left to reduce the clicks to just 2 (click + confirm)

This can be done using selector-observer