* Add "Follow OS theme" option
* Update App.axaml.cs
* Add "Follow OS theme" option
* Update App.axaml.cs
* Remove `this`
* Remove annotation for nullable reference
* Change into switch expression to make it concise
* Change comments to XML docs
* Update en_US.json
* Fix icons in About dialog do not response to "auto" theme
The theme icons seemingly use Dark variant event when the OS theme is light. In addition, I added ThemeManager common to make it accessible for both App and AboutWindow
* Newline at the end
* newline moment
* Update ThemeManager.cs
* bait to switch to lf
* change to lf
* temp. revert
* Add back ThemeManager.cs common, pls pass the format check
* I found the mistake: should have put `ThemeManager.OnThemeChanged();` in try block
Finally solve the formatting check
* test formatting
* Update App.axaml.cs
* Ok i seem to forget to add version lol
* Fix info CA1816
