Upgrade: Bump highlight.js from 11.4.0 to 11.5.1

Bumps [highlight.js](https://github.com/highlightjs/highlight.js) from 11.4.0 to 11.5.1.
- [Release notes](https://github.com/highlightjs/highlight.js/releases)
- [Changelog](https://github.com/highlightjs/highlight.js/blob/11.5.1/CHANGES.md)
- [Commits](highlightjs/highlight.js@11.4.0...11.5.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Close: #1015

Author: dependabot[bot]

package-lock.json

@@ -9,7 +9,7 @@
     "ejs": "^3.1.7",
     "express": "^4.17.1",
     "globby": "^13.1.1",
-    "highlight.js": "^11.0.0",
+    "highlight.js": "^11.5.1",
     "hint": "^6.1.12",
     "js-yaml": "^4.1.0",
     "lodash": "^4.17.15",