Highlight all supported languages with the highlight.js worker

What does this MR do and why?

As part of &7146 we've created a highlight worker so that the task of highlighting does not happen on the main thread.

Currently we're only highlighting JSON files with our highlight worker, this MR ensures we highlight all supported languages with the worker.

Screenshots or screen recordings

No visual changes are expected

Before	After

How to set up and validate locally

⚠ Run echo "Feature.enable(:highlight_js_worker)" | gdk rails c

Webpack

1. Open any source code blob via the repository files browser
2. The syntax should highlight as expected

Vite

1. Run echo "Feature.enable(:vite)" | gdk rails c
2. Launch bundle exec vite dev
3. Restart GDK
4. Open any source code blob via the repository files browser
5. The syntax should highlight as expected

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #415753 (closed)