docs: improved going further modules documentation (#19219)

Co-authored-by: Rafael Magalhaes <rafael.magalhaes@yapily.com>

docs/2.guide/3.going-further/3.modules.md

@@ -294,6 +294,42 @@ export default defineNuxtModule({
 })
 ```
 
+### Adding Composables
+
+If your module should provide composables, you can use the `addImports` utility to add them as auto-imports for Nuxt to resolve.
+
+```ts
+import { defineNuxtModule, addImports, createResolver } from '@nuxt/kit'
+
+export default defineNuxtModule({
+  setup(options, nuxt) {
+    const resolver = createResolver(import.meta.url)
+    addImports({
+      name: 'useComposable', // name of the composable to be used
+      as: 'useComposable', 
+      from: resolver.resolve('runtime/composables/useComposable') // path of composable 
+    })
+  }
+})
+```
+
+Alternatively, you can add an entire directory by using `addImportsDir`.
+
+```ts
+import { defineNuxtModule, addImportsDir, createResolver } from '@nuxt/kit'
+
+export default defineNuxtModule({
+  setup(options, nuxt) {
+    const resolver = createResolver(import.meta.url)
+    addImportsDir(resolver.resolve('runtime/composables'))
+  }
+})
+```
+
+::alert
+Note that auto-imports are not enabled for files within `node_modules` for performance reasons, so the module starter [deliberately disables them](https://github.com/nuxt/starter/blob/module/.nuxtrc#L1) while developing a module. If you are using the module starter, auto-imports will not be enabled in your playground either.
+::
+
 ### Clean Up Module
 
 If your module opens, handles or starts a watcher, you should close it when the Nuxt lifecycle is done. For this, use the `close` hook: