services/searxng: use url instead of just port number for service

services/searxng.nix

@@ -65,7 +65,7 @@ in
         service = "searxng";
       };
       http.services.searxng = {
-        loadbalancer.servers.port = searxngPort;
+        loadbalancer.servers.url = "127.0.0.1:${toString searxngPort}";
       };
     };
   };