Update plugin-options.md

For #294

Author: rohit-gohri

website/docs/getting-started/plugin-options.md

@@ -14,6 +14,10 @@ Either a file path to an OpenAPI YAML/JSON file, or a url to one hosted on some
 
 Route URL at which docs would be available, this will use the theme component `@theme/ApiDoc` from `docusaurus-theme-redoc` to render the page. You can also skip this option and render the docs as you wish using a custom page.
 
+### url (optional, string: download url)
+
+A url pointing to an OpenAPI spec. This will be used as download url and spec will be used for rendering. This might be needed because by default the download url will point to a processed and parsed file generated by redocusaurus.
+
 ### layout (optional, object: layoutProps)
 
 An object to pass as layout props. Useful to set title/description of the page. See all properties available [here](https://github.com/rohit-gohri/redocusaurus/blob/main/packages/docusaurus-plugin-redoc/src/options.ts#L3).