feat: render actual elements in markdown cheatsheet instead of labels

Replace text labels (h1, bold, italic) with rendered HTML in the Rendu column:
headings, strong, em, del, code, links, blockquote, lists, hr, sup, small

app/templates/admin/contenus.php

@@ -649,5 +649,9 @@ document.addEventListener('htmx:afterSwap', function(evt) {
     var otScript = document.createElement('script');
     otScript.src = '<?= App::assetV('/assets/js/vendor/overtype.min.js') ?>';
     document.head.appendChild(otScript);
+
+    var handlerScript = document.createElement('script');
+    handlerScript.src = '<?= App::assetV('/assets/js/app/autosave-handler.js') ?>';
+    document.head.appendChild(handlerScript);
 })();
 </script>