Multiple improvements for comment edit diff (#21990)
- Use explicit avatar size so when JS copies the HTML, the size gets
copied with it
- Replace icon font use with SVG
- Improve styling and diff rendering
- Sort lists in `svg.js`
Fixes: https://github.com/go-gitea/gitea/issues/21924
<img width="933" alt="Screenshot 2022-11-30 at 17 52 17"
src="https://user-images.githubusercontent.com/115237/204859608-f322a8f8-7b91-45e4-87c0-82694e574115.png">
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>