archwiki: workaround another hard-coded wgScriptPath in the new Vector theme

Without this change, "Search for pages containing" doesn't work.

roles/archwiki/templates/nginx.d.conf.j2

@@ -80,6 +80,11 @@ server {
         return 302 /rest.php/v1/search/title$is_args$args;
     }
 
+    # Workaround for "Search for pages containing" hard-coded to /w/index.php
+    location ^~ /w/index.php {
+        return 302 /index.php$is_args$args;
+    }
+
     # special case for '/load.php' type URLs to cache css/js in nginx to relieve php-fpm
     location = /load.php {
         access_log   /var/log/nginx/{{ archwiki_domain }}/access.log main;