Some minor changes: coherent distances between heading and descriptions, drop a divider between time tracking related sections.
### Test
1. Go to an issue, add some time tracking and potentially dependencies.
2. Observe improved distances with a user with and once with a user without write permission.
The content of the `release-notes/<pull request number>.md` file will serve as the basis for the release notes. If the file does not exist, the title of the pull request will be used instead.
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/12786
Reviewed-by: 0ko <0ko@noreply.codeberg.org>
