`comment-region` doesn't work out-of-the-box

[sogaiu]

I get No comment syntax is defined. Use: in the minibuffer when invoking comment-region.

I don't know if the treesit stuff will somehow make this all work via some clever means (or if there's already a way), but for the moment the traditional method of:

(setq-local comment-start ";")

in an appropriate location within the define-derived-mode form seems to work.

[dannyfreeman]

This is fixed, thank you @sogaiu