Update index.md to publish assets (got idea from...

Update index.md to publish assets (got idea from https://stackoverflow.com/questions/76925036/civicrm-menu-not-showing-in-drupal-9)

docs/drupal/index.md

@@ -65,6 +65,7 @@ cd /var/www/d9.example.org
 composer config extra.enable-patching true
 composer config minimum-stability dev
 composer require civicrm/civicrm-{core,packages,drupal-8}:'~5.42'
+composer civicrm:publish
 ```
 
 You should adjust the example path (`/var/www/d9.example.org`) and the example version (`~5.42`) as needed.