tools: update doc to highlight.js@11.8.0

PR-URL: https://github.com/nodejs/node/pull/47786
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

tools/doc/package.json

@@ -7,7 +7,7 @@
     "node": ">=14.8.0"
   },
   "devDependencies": {
-    "highlight.js": "^11.7.0",
+    "highlight.js": "^11.8.0",
     "js-yaml": "^4.1.0",
     "rehype-raw": "^6.1.1",
     "rehype-stringify": "^9.0.3",