- Removed all jQuery AJAX calls and replaced with htmx
- Tested the code diff expansion buttons functionality and it works as
before plus a loading indicator
# Demo using `htmx` instead of jQuery AJAX
![action](https://github.com/go-gitea/gitea/assets/20454870/afba7442-ed56-4d39-b764-835d1f6c3a9c)
Signed-off-by: Yarden Shoham <git@yardenshoham.com>