fix: make TOC title and entries visible at the same time (#1711)

When internet connection speeds are poor, there is a chance that the title of the TOC will appear earlier than its entries, causing a visual cutoff.

_javascript/modules/components/toc.js

@@ -9,5 +9,7 @@ export function toc() {
       orderedList: false,
       scrollSmooth: false
     });
+
+    document.getElementById('toc-wrapper').classList.remove('d-none');
   }
 }