Vendor highlight.js and add scheme language support to /docs.

- Ran: `node tools/build.js :common scheme`
- Upgrade from: `Highlight.js v10.1.1 (93fd0d73)` (June 2020)
- Upgraded to : `Highlight.js v11.10.0 (263980c628)` (August 2024)

docs/README.md

@@ -26,3 +26,22 @@ Putting binary assets such as images in the Git repository will bloat the reposi
 The table of contents files (`theme/page-toc.js` and `theme/page-doc.css`) were initially generated by [`mdbook-pagetoc`](https://crates.io/crates/mdbook-pagetoc).
 
 Since all these preprocessor does is generate the static assets, we don't need to keep it around once they have been generated.
+
+### Highlight.js
+
+mdBook by default uses Highlight.js with a custom theme for syntax highlighting with automatic language detection turned off for a list subset of common [supported languages](https://rust-lang.github.io/mdBook/format/theme/syntax-highlighting.html#supported-languages).
+
+We've updated with a highlight.js that supports additional languages (`scheme`).
+To regenerate highlight.js run the following:
+
+```
+git clone https://github.com/highlightjs/highlight.js
+cd highlight.js
+git checkout 10-stable
+node tools/build.js :common scheme
+
+ZED_FOLDER=~/code/zed
+cp build/highlight.min.js $ZED_FOLDER/docs/theme/highlight.js
+```
+
+Be sure to edit the code block above to include the any added languages (after `scheme`).