Dotty highlighting for Scala sources?

[armanbilge]

Currently, Scala 3 "Dotty" highlighting is activated only if the sources are marked as dotty:

```dotty

In my case, the problem is that this doesn't work with mdoc:

```dotty mdoc

I'm not sure if there's any good way to resolve this, without sacrificing either Scala 2 or Scala 3 syntax highlighting.