docs: mention possibility of prerendering api routes (#31234)

docs/1.getting-started/9.prerendering.md

@@ -144,6 +144,7 @@ You can use this at runtime within a [Nuxt context](/docs/guide/going-further/nu
 ```vue [pages/index.vue]
 <script setup>
 prerenderRoutes(["/some/other/url"]);
+prerenderRoutes("/api/content/article/my-article");
 </script>
 
 <template>

docs/3.api/3.utils/prerender-routes.md

@@ -28,3 +28,19 @@ prerenderRoutes(['/', '/about'])
 ::note
 In the browser, or if called outside prerendering, `prerenderRoutes` will have no effect.
 ::
+
+You can even prerender API routes which is particularly useful for full statically generated sites (SSG) because you can then `$fetch` data as if you have an available server!
+
+```js
+prerenderRoutes('/api/content/article/name-of-article')
+
+// Somewhere later in App
+const articleContent = await $fetch('/api/content/article/name-of-article', {
+  responseType: 'json',
+})
+```
+
+::warning
+Prerendered API routes in production may not return the expected response headers, depending on the provider you deploy to. For example, a JSON response might be served with an `application/octet-stream` content type.
+Always manually set `responseType` when fetching prerendered API routes.
+::