Add styling for "no results found" in the type ahead search box (#14958)

* basic no results styling

* tweaks

frontend/src/metabase/nav/components/SearchBar.jsx

@@ -95,9 +95,11 @@ export default class SearchBar extends React.Component {
   renderResults(results) {
     if (results.length === 0) {
       return (
-        <li>
-          <Icon name="alert" />
-          {t`No results`}
+        <li className="flex flex-column align-center justify-center p4 text-medium text-centered">
+          <div className="my3">
+            <Icon name="search" mb={1} size={24} />
+            <h3 className="text-light">{t`No results found`}</h3>
+          </div>
         </li>
       );
     } else {