improve syntax highlighting

[maks]

Currently on Lua and Python have custom keyword highlighting.

[kb-1000]

Also, the colors look terrible here:

This was at least how it looked after installing the app...

[maks]

@kb-1000 thats a known issue due to you using Dark theme in the app and the syntax highlighting colours not having support for that. But thats a separate concern, so please file that as a new issue, this issue is specifically regarding supporting syntax highlighting for more languages.

[kb-1000]

Dark theme was the default, though.