docs: add a link to Docus layer nuxt config file (nuxt#21742)

docs/2.guide/3.going-further/7.layers.md

@@ -61,6 +61,10 @@ Additionally, certain other files in the layer directory will be auto-scanned an
 
 ::
 
+::alert{type="info"}
+If you're interested in deepening your understanding about layers, consider examining [a fully fleshed out `nuxt.config.ts` file on the Docus platform](https://github.com/nuxt-themes/docus/blob/main/nuxt.config.ts).
+::
+
 ## Starter Template
 
 To get started you can initialize a layer with the [nuxt/starter/layer template](https://github.com/nuxt/starter/tree/layer). This will create a basic structure you can build upon. Execute this command within the terminal to get started: