Bump highlight.js from 11.6.0 to 11.9.0

Bumps [highlight.js](https://github.com/highlightjs/highlight.js) from 11.6.0 to 11.9.0.
- [Release notes](https://github.com/highlightjs/highlight.js/releases)
- [Changelog](https://github.com/highlightjs/highlight.js/blob/main/CHANGES.md)
- [Commits](highlightjs/highlight.js@11.6.0...11.9.0)

---
updated-dependencies:
- dependency-name: highlight.js
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -29,7 +29,7 @@
   "dependencies": {
     "@traptitech/traq": "^3.17.0-1",
     "@traptitech/traq-markdown-it": "^6.2.1",
-    "highlight.js": "^11.6.0",
+    "highlight.js": "^11.9.0",
     "idb-keyval": "^6.2.0",
     "katex": "^0.16.2",
     "lit-html": "^2.3.1",