- general English improvements
- separated the header of Language part in user settings into a new string for better translatability
- made that header contain "Default", just like the theme one, because this is how this actually works: the bottom selector saves the language temporarily, the selector in the settings saves it permanently. Not many users know about this difference. This clarification will help some
- removed some of "Manage" from the headers where they aren't really needed. This improves the consistency with some other headers
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/3733
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>