Add config option for Highlight.js

[caendesilva]

It's no secret that I love Torchlight. But for some it may be bothersome to have to get an API key and set it as a CI secret. So I'm wondering if we should have a config option for a client-side library like Highlight.js.

It's fairly easy to add. See https://gist.github.com/caendesilva/84e8399b3255b825f02f92f33e4ebe64

<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/styles/dark.min.css">
<script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/highlight.min.js"></script>
<script>hljs.highlightAll();</script>
<style>.prose :where(pre):not(:where([class~=not-prose] *)) { background-color: #303030 } </style>
<style>pre code.hljs { padding: 0; }</style>

[caendesilva]

Since it's easy to add, and because adding this could open up a large feature scope where we might want to support a whole bunch of different libraries, it's probably better to make it easier to set HTML from the config. It's still (and has been for a long time) possible to extend the head and scripts Blade components, but when working with things like anonymous projects it becomes a bit cumbersome. Having a nice way to set this in the hyde.yml file would be really nice for cloud setups. Closing in favour of #1542 (until/unless this feature becomes requested by others).