docs: add info about dynamic nested routes (#22862)

docs/2.guide/2.directory-structure/1.pages.md

@@ -134,6 +134,10 @@ if (route.params.group === 'admins' && !route.params.id) {
 </script>
 ```
 
+::alert{type="info"}
+Named parent routes will take priority over nested dynamic routes. For the `/foo/hello` route, `~/pages/foo.vue` will take priority over `~/pages/foo/[slug].vue` . Use `~/pages/foo/index.vue` and `~/pages/foo/[slug].vue` to match `/foo` and `/foo/hello` with different pages,.
+::
+
 ## Catch-all Route
 
 If you need a catch-all route, you create it by using a file named like `[...slug].vue`. This will match _all_ routes under that path.