docs: example using useMeta with definePageMeta (#3552)

docs/content/3.docs/1.usage/3.meta-tags.md

@@ -58,3 +58,29 @@ export default {
 }
 </script>
 ```
+
+## Example: usage with definePageMeta
+
+You can use `definePageMeta` along with `useMeta` to set metadata based on the current route.
+
+For example, to include the page title alongside your app name, first define your page title:
+
+```vue{}[pages/some-page.vue]
+<script setup>
+definePageMeta({
+  title: 'Some Page'
+})
+</script>
+```
+
+And then in your layout file:
+
+```vue{}[layouts/default.vue]
+<script setup>
+const route = useRoute()
+
+useMeta({
+  title: computed(() => `App Name - ${route.meta.title}`)
+})
+</script>
+```