Extract Highlight controller

assets/controllers/highlight_controller.js

@@ -0,0 +1,11 @@
+import { Controller } from '@hotwired/stimulus';
+import 'highlight.js/styles/atom-one-light.css';
+import hljs from 'highlight.js';
+
+export default class extends Controller {
+  connect() {
+    this.element.querySelectorAll('pre code').forEach((element) => {
+      hljs.highlightElement(element);
+    });
+  }
+}