Update link.md (#20435)

Added the `locale` prop in the Link documentation. At the moment it is only stated in the i18n doc.

docs/api-reference/next/link.md

@@ -61,6 +61,7 @@ export default Home
 - [`replace`](#replace-the-url-instead-of-push) - Replace the current `history` state instead of adding a new url into the stack. Defaults to `false`
 - [`scroll`](#disable-scrolling-to-the-top-of-the-page) - Scroll to the top of the page after a navigation. Defaults to `true`
 - [`shallow`](/docs/routing/shallow-routing.md) - Update the path of the current page without rerunning [`getStaticProps`](/docs/basic-features/data-fetching.md#getstaticprops-static-generation), [`getServerSideProps`](/docs/basic-features/data-fetching.md#getserversideprops-server-side-rendering) or [`getInitialProps`](/docs/api-reference/data-fetching/getInitialProps.md). Defaults to `false`
+- `locale` - The active locale is automatically prepended. `locale` allows for providing a different locale. When `false` `href` has to include the locale as the default behavior is disabled.
 
 ## If the route has dynamic segments