This (free) extension makes it easy to add highlight.js to your website, it supports many themes and includes support for most common languages (html, css, javascript, cpp, php etc).
Online demo
https://www.wysiwygwebbuilder.com/support/nineimagesgallery.html
More information
https://www.wysiwygwebbuilder.com/highlightjs.html
You can also download the new extension via the Extension Manager: Menu->Tools->Extension Manager->Online Gallery->Miscellaneous
This extension is from my private collection. It is provided "AS IS".
Please read the included documentation for help.
https://www.buymeacoffee.com/wysiwygwb