Update i18n fields in docs (#26492)

Closes: #24991

## Documentation / Examples

- [x] Make sure the linting passes

Author: ijjk

docs/advanced-features/i18n-routing.md

@@ -52,6 +52,9 @@ module.exports = {
       {
         domain: 'example.fr',
         defaultLocale: 'fr',
+        // an optional http field can also be used to test
+        // locale domains locally with http instead of https
+        http: true,
       },
     ],
   },

docs/api-reference/next/router.md

@@ -49,6 +49,7 @@ The following is the definition of the `router` object returned by both [`useRou
 - `locale`: `String` - The active locale (if enabled).
 - `locales`: `String[]` - All supported locales (if enabled).
 - `defaultLocale`: `String` - The current default locale (if enabled).
+- `domainLocales`: `Array<{domain, defaultLocale, locales}>` - Any configured domain locales.
 - `isReady`: `boolean` - Whether the router fields are updated client-side and ready for use. Should only be used inside of `useEffect` methods and not for conditionally rendering on the server.
 - `isPreview`: `boolean` - Whether the application is currently in [preview mode](/docs/advanced-features/preview-mode.md).