Generate Kakoune UI faces

[igor-ramazanov]

Right now we generate only kak-tree-sitter syntax highlighting faces. However, to make the experience consistent we will also need to generate Kakoune UI faces.

Useful links:

• https://docs.helix-editor.com/themes.html#interface
• https://github.com/mawww/kakoune/blob/master/doc/pages/faces.asciidoc#built-in-faces
• https://delapouite.github.io/kakoune-ink/