style: Re-apply style normalisation

Originally this was manually applied with;

```sh
nixpkgs-fmt **.nix && statix fix
```

but I overlooked the fact that `**.nix` would only expand to files in
the root (I should have used `**/*.nix`).

Previous commit adds `nix fmt` support which passes `.` to `nixpkgs-fmt`
(if no other path is explicitly specified when running `nix fmt`).

This commit includes the changes made by running `nix fmt`.

example/stand-alone/configuration.nix

@@ -1,8 +1,8 @@
-{
-  pkgs,
-  lib,
-  ...
-}: let
+{ pkgs
+, lib
+, ...
+}:
+let
   # We just import from the repository for testing here:
   disko = import ../../. {
     inherit lib;
@@ -41,7 +41,8 @@
       };
     };
   };
-in {
+in
+{
   imports = [
     (disko.config cfg)
   ];

tests/bcachefs.nix

@@ -14,11 +14,13 @@ makeDiskoTest {
   extraConfig = {
     boot.supportedFilesystems = [ "bcachefs" ];
     # disable zfs so we can support latest kernel
-    nixpkgs.overlays = [(final: super: {
+    nixpkgs.overlays = [
+      (final: super: {
         zfs = super.zfs.overrideAttrs (_: {
           meta.platforms = [ ];
         });
-    })];
+      })
+    ];
     boot.kernelPackages = pkgs.lib.mkForce (pkgs.recurseIntoAttrs (pkgs.linuxPackagesFor linux-bcachefs));
   };
 }

tests/default.nix

@@ -6,9 +6,11 @@ let
   lib = pkgs.lib;
   makeDiskoTest = (pkgs.callPackage ./lib.nix { inherit makeTest eval-config; }).makeDiskoTest;
 
-  evalTest = name: configFile: let
+  evalTest = name: configFile:
+    let
       disko-config = import configFile;
-  in {
+    in
+    {
       "${name}-tsp-create" = pkgs.writeScript "create" ((pkgs.callPackage ../. { }).create disko-config);
       "${name}-tsp-mount" = pkgs.writeScript "mount" ((pkgs.callPackage ../. { }).mount disko-config);
     };