While I wouldn't expect vimscript
to be immediately available for highlighting, I think other languages aren't available either. I just tried to add it to this answer using both <!-- language: bash -->
and <!-- language: lang-sh -->
to no effect in the edit preview (so I didn't submit the suggestion).
.vimrc
where highlighting would be helpful. From my experience, highlighting may not appear until you post and scroll through the page... Or unless the correct language is a tag.vimscript
here. For the record there is no feature or pull request on GitHub, at the moment.