Are you talking about reading view or editing? For reading view, we still use Prism.js and it’s highlighted the same way as it did before. For editing view, because it’s a live editor, we can’t use Prism.js and therefore we have to use CodeMirror’s own highlighters which is much more limited in what tokens it can emit.
Unfortunately, I can’t just slap Prism.js on the editor to make it emit better tokens. Someone will either have to re-write all the CodeMirror language parsers or somehow make a prism-to-codemirror shim, both of which require a lot of work.
We are going to consider this a feature request, to implement (and improve) the syntax highlighter when working in the editor. Bug reports are reserved for issues that are unintentional from our part. While I agree that this specific issue is not desired, it is unfortunately intentional due to technical limitations, at least for now.