treewide: Format all Nix files

Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:

  nix-build ci -A fmt.check

This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).

This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).

Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](8616af08d9/maintainers/scripts/auto-rebase).

If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.

nixos/modules/services/networking/snowflake-proxy.nix

@@ -1,4 +1,9 @@
-{ config, lib, pkgs, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 
 with lib;
 
@@ -41,7 +46,8 @@ in
       wantedBy = [ "network-online.target" ];
       serviceConfig = {
         ExecStart =
-          "${pkgs.snowflake}/bin/proxy " + concatStringsSep " " (
+          "${pkgs.snowflake}/bin/proxy "
+          + concatStringsSep " " (
             optional (cfg.broker != null) "-broker ${cfg.broker}"
             ++ optional (cfg.capacity != null) "-capacity ${builtins.toString cfg.capacity}"
             ++ optional (cfg.relay != null) "-relay ${cfg.relay}"
@@ -67,11 +73,18 @@ in
         ProtectProc = "invisible";
         ProtectKernelModules = true;
         ProtectKernelTunables = true;
-        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_UNIX" ];
+        RestrictAddressFamilies = [
+          "AF_INET"
+          "AF_INET6"
+          "AF_UNIX"
+        ];
         RestrictNamespaces = true;
         RestrictRealtime = true;
         SystemCallArchitectures = "native";
-        SystemCallFilter = [ "@system-service" "~@privileged" ];
+        SystemCallFilter = [
+          "@system-service"
+          "~@privileged"
+        ];
         UMask = "0077";
       };
     };