docs: show possible similar pages on 404 page (#13840)

* docs: show possible similar pages on 404 page

* fix 404 page in api reference

www/apps/cloud/app/not-found.mdx

@@ -2,7 +2,7 @@
 hide_content_menu: true
 ---
 
-import { CardList, H1 } from "docs-ui"
+import { CardList, H1, SimilarPages } from "docs-ui"
 import {
   BookOpen,
   AcademicCapSolid,
@@ -18,14 +18,20 @@ export const metadata = {
 
 The page you were looking for isn't available.
 
+If you're looking for Medusa v1 documentation, it's been moved to [docs.medusajs.com/v1](https://docs.medusajs.com/v1).
+
 If you think this is a mistake, please [report this issue on GitHub](https://github.com/medusajs/medusa/issues/new?assignees=&labels=type%3A+docs&template=docs.yml).
 
+<SimilarPages />
+
+## Other Resources
+
 <CardList
   itemsPerRow={2}
   items={[
     {
       title: "Get Started Docs",
-      href: "/",
+      href: "!docs!/learn",
       icon: BookOpen
     },
     {