I should see at least some code highlighting when editing QLText

(User Story, Investigate , Priority: Critical, Test Status: No automated tests yet , Reported By Justin du Coeur, )
UX, Editor
Summary: Currently, the "editor" is a plain textarea. This sucks. It would suck less if we had syntax highlighting, as the first baby step towards a decent IDE.
It looks like this almost certainly means integration with either CodeMirror or Ace -- more likely CodeMirror, which looks to be more powerful. (Note that CodeMirror has a "simple mode" definition API that is very similar to Ace, and would likely suffice for QL.)
The primary bottleneck here is that CodeMirror is a modern JS library, and expects to be used in modern JS ways, using something like CommonJS. I believe that that implies that we need to switch over to using scalajs-bundler. That's probably a good idea on general principles, since Sebastian is trying to phase out JSDependencies, but looks to be a non-trivial project.