We've been using Rouge to syntax-highlight our Scala snippets for many many years now, dating back to (iirc) even before the existence of Scala 3
But Rouge seems to lack full support for Scala 3 at present, as per rouge-ruby/rouge#1885
an alternative highlighter, Pygments, does have some Scala 3 support, as per pygments/pygments#1694 , but probably it's fallen a bit out of date
and there are also other highlighters out there, for example:
It would be nice not to have to maintain so many different highlighters. Perhaps we could switch to Linguist or Treesitter for our websites.