[install-auto] add note about dev toolbar - merge after 5538 (#5595)

src/content/docs/en/install/auto.mdx

@@ -85,6 +85,8 @@ If all goes well, Astro should now be serving your project on [http://localhost:
 
 Astro will listen for live file changes in your `src/` directory, so you will not need to restart the server as you make changes during development.
 
+When viewing your site in the browser, you'll have access to the [Astro dev toolbar](/en/reference/configuration-reference/#dev-toolbar-options). As you build, it will help you inspect your [islands](/en/concepts/islands/), spot accessibility issues, and more.
+
 If you aren't able to open your project in the browser, go back to the terminal where you ran the `dev` command and look to see if an error occurred, or if your project is being served at a different URL than the one linked to above.
 
 ## Starter Templates