- Added a number of common themes to our support matrix:
- AtomOneDark
- Dracula
- VS
- GitHub
- GoogleCode
- XCode
- ... Admittedly these all were randomly picked, we could probably curate these better...
- Added a new `ThemeDialog` UI that can be accessed via `/theme`. It shows your currentlyt available themes and allows you to change them freely. It does **not**:
- Save the theme between sessions
- Allow you to hit escape
- Show a preview prior to selection.
- These themes are from reacts highlight js library.
Fixes https://b.corp.google.com/issues/412797985
