docs: change info to danger for pages root element

docs/content/2.guide/3.directory-structure/15.app.md

@@ -32,8 +32,8 @@ If you have a [`pages/`](/guide/directory-structure/pages) directory, to display
 </template>
 ```
 
-::alert{type=info}
-Since Nuxt 3 uses [`<Suspense>`](https://vuejs.org/guide/built-ins/suspense.html#suspense) inside `<NuxtPage>`, we recommend to wrap it into a single root element.
+::alert{type=danger}
+Since Nuxt 3 uses [`<Suspense>`](https://vuejs.org/guide/built-ins/suspense.html#suspense) inside `<NuxtPage>`, it cannot be set as a root element.
 ::
 
 ::alert{type=warning}