style: Switch to nixfmt from nixpkgs-fmt

Most of the ecosystem has moved to this formatter,
and many people configured their editors to autoformat it with this formatter.

Closes: https://git.snix.dev/snix/snix/issues/62
Change-Id: Icf39e7836c91fc2ae49fbe22a40a639105bfb0bd
Reviewed-on: https://cl.snix.dev/c/snix/+/30671
Reviewed-by: Florian Klink <flokli@flokli.de>
Tested-by: besadii
Autosubmit: Ilan Joselevich <personal@ilanjoselevich.com>

ops/modules/www/base.nix

@@ -2,7 +2,10 @@
 
 {
   config = {
-    networking.firewall.allowedTCPPorts = [ 80 443 ];
+    networking.firewall.allowedTCPPorts = [
+      80
+      443
+    ];
 
     security.acme = {
       acceptTerms = true;

ops/modules/www/tempo.snix.dev.nix

@@ -6,7 +6,8 @@
 
   services.nginx = {
     upstreams.tempo = {
-      servers."${config.services.tempo.settings.distributor.receivers.otlp.protocols.http.endpoint}" = { };
+      servers."${config.services.tempo.settings.distributor.receivers.otlp.protocols.http.endpoint}" =
+        { };
     };
 
     virtualHosts."tempo.snix.dev" = {