chore: seo best practices (#382)

Author: chdeskur

fern/products/docs/pages/customization/frontmatter.mdx

@@ -245,6 +245,8 @@ Currently, relative paths are _not_ supported for this field.
 ## SEO metadata
 
 <Note title="SEO Best Practices">
+Looking to set metadata across the entire site? [Use the metadata field in the `docs.yml` file](/learn/docs/customization/what-is-docs-yml#metadata-configuration).
+
 When configuring SEO metadata, ensure your titles and descriptions are unique, descriptive, and relevant to the page content. Keep descriptions between 150-160 characters for optimal display in search results.
 </Note>