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/cluster/kubernetes/proxy.nix

@@ -1,4 +1,10 @@
-{ config, lib, options, pkgs, ... }:
+{
+  config,
+  lib,
+  options,
+  pkgs,
+  ...
+}:
 
 with lib;
 
@@ -9,7 +15,10 @@ let
 in
 {
   imports = [
-    (mkRenamedOptionModule [ "services" "kubernetes" "proxy" "address" ] ["services" "kubernetes" "proxy" "bindAddress"])
+    (mkRenamedOptionModule
+      [ "services" "kubernetes" "proxy" "address" ]
+      [ "services" "kubernetes" "proxy" "bindAddress" ]
+    )
   ];
 
   ###### interface
@@ -62,16 +71,24 @@ in
       description = "Kubernetes Proxy Service";
       wantedBy = [ "kubernetes.target" ];
       after = [ "kube-apiserver.service" ];
-      path = with pkgs; [ iptables conntrack-tools ];
+      path = with pkgs; [
+        iptables
+        conntrack-tools
+      ];
       serviceConfig = {
         Slice = "kubernetes.slice";
         ExecStart = ''
           ${top.package}/bin/kube-proxy \
           --bind-address=${cfg.bindAddress} \
-          ${optionalString (top.clusterCidr!=null)
-            "--cluster-cidr=${top.clusterCidr}"} \
-          ${optionalString (cfg.featureGates != {})
-            "--feature-gates=${concatStringsSep "," (builtins.attrValues (mapAttrs (n: v: "${n}=${trivial.boolToString v}") cfg.featureGates))}"} \
+          ${optionalString (top.clusterCidr != null) "--cluster-cidr=${top.clusterCidr}"} \
+          ${
+            optionalString (cfg.featureGates != { })
+              "--feature-gates=${
+                concatStringsSep "," (
+                  builtins.attrValues (mapAttrs (n: v: "${n}=${trivial.boolToString v}") cfg.featureGates)
+                )
+              }"
+          } \
           --hostname-override=${cfg.hostname} \
           --kubeconfig=${top.lib.mkKubeConfig "kube-proxy" cfg.kubeconfig} \
           ${optionalString (cfg.verbosity != null) "--v=${toString cfg.verbosity}"} \