Add comment to search input shortcut code

docs/source/_assets/js/app.js

@@ -14,8 +14,9 @@ Prism.highlightAll()
 anchors.options = { placement: 'left', class: 'text-slate-light' };
 anchors.add();
 
+// Add shortcut to search input when pressing the "/" key
 document.onkeyup = function (e) {
     if (e.which == 191) {
         document.getElementById('docsearch').focus();
     }
-};
+};