Add scala3.js
to your webpage and register the language in hljs.
<script>
hljs.registerLanguage('scala3', highlightDotty);
hljs.registerAliases('dotty', 'scala3');
</script>
Then use hljs as usual, e.g.
<pre><code class="language-scala3">enum ItWorks(val x: Boolean)</code></pre>
<script>
hljs.initHighlightingOnLoad();
</script>