add sitemap and robots.txt

Author: ethanpalm

settings/seo.mdx

@@ -138,9 +138,9 @@ You can preview how your meta tags will appear on different platforms using [met
 }
 ```
 
-## Sitemaps
+## Sitemaps and robots.txt files
 
-Mintlify automatically generates a `sitemap.xml` file and a `robots.txt` file. Simply navigate to `/sitemap.xml` to see your sitemap.
+Mintlify automatically generates a `sitemap.xml` file and a `robots.txt` file. You can view your sitemap by appending `/sitemap.xml` to your documentation site's URL.
 
 Only pages included in your `docs.json` are included by default. To include hidden links, add `seo.indexing` to your `docs.json`:
 
@@ -150,6 +150,10 @@ Only pages included in your `docs.json` are included by default. To include hidd
 }
 ```
 
+### Custom sitemaps and robots.txt files
+
+To add a custom `sitemap.xml` or `robots.txt` file, create a `sitemap.xml` or `robots.txt` file at the root of your project. Adding a custom file will override the automatically generated file of the same name. If you delete a custom file, the default file will be used again.
+
 ## Disabling indexing
 
 If you want to stop a page from being indexed by search engines, you can include the following in the [frontmatter](pages) of your page: