Feature Description

Chroma is used to highlight code in gitea. Several issues opened are regarding support for new languages, link file extensions and even styles.
Since chroma uses a style+lexer combination for highlighting code, I suggest the following solution to fit all needs:

1 Priority:
The user can customise a particular file extension with the following lines on app.ini:

[highlight.mapping]
.mo = path_to_lexer.xml, path_to_style_normal, path_to_style_dark

Style types are optional, they can be files accessible by the server or the name of any style included in chroma.

2 Priority
If no custom definition is used for this file extension, the user can link an file extension to a chroma supported language:

[highlight.mapping]
.omnijs = JavaScript

Or optional:
.omnijs = JavaScript, path_to_style_normal, path_to_style_dark

With the same consideration of styles than 1.

3 Priority
If none is defined, then use the chroma/gitea defaults for lexer and styles

Screenshots

No response