highlight editor fix

pages/_includes/cards/icons.html

@@ -15,7 +15,7 @@
 						{% include ui/icon.html svg-icon=first-icon-svg %}
 					</div>
 					<h2 class="mt-2" data-icon-preview-title>{{ first-icon-name }}</h2>
-					<pre class="user-select-all" style="max-height: 10rem"><code data-icon-preview-code>{{ first-icon-svg | escape }}</code></pre>
+					<pre class="highlight user-select-all" style="max-height: 10rem"><code data-icon-preview-code>{{ first-icon-svg | escape }}</code></pre>
 				</div>
 			</div>
 			<div class="col">