clarify asset location for download component (#1067)

Author: chdeskur

fern/products/docs/pages/component-library/default-components/embed.mdx

@@ -86,7 +86,7 @@ Fern also implements a custom component for embedding downloadable assets:
 Enable users to download assets from within your documentation, instead of linking to them, by using the `<Download>` component.
 
 <ParamField path="src" type="string" required={true}>
-  Path to your local asset (relative to current MDX file)
+  Path to your local asset (relative to current MDX file). The asset must be located within the `fern` folder.
 </ParamField>
 
 <ParamField path="children" type="React.ReactNode" required={true}>