chore: use new syntax for css variables (#3258)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

docs/app/components/content/examples/input-menu/InputMenuFilterFieldsExample.vue

@@ -33,7 +33,7 @@ const { data: users, status } = await useFetch('https://jsonplaceholder.typicode
     <template #item-label="{ item }">
       {{ item.label }}
 
-      <span class="text-[var(--ui-text-muted)]">
+      <span class="text-(--ui-text-muted)">
         {{ item.email }}
       </span>
     </template>