Install a formatter for nix

nix/module/home-manager.nix

@@ -1,5 +1,4 @@
-
-{email}: {pkgs, ...}: {
+{ email }: { pkgs, ... }: {
   home.file.".emacs.d/early-init.el".source = ../config/emacs/early-init.el;
   home.file.".emacs.d/tree-sitter/libtree-sitter-swift.dylib".source = ../config/emacs/tree-sitter/libtree-sitter-swift.dylib;
   home.file.".clojure/deps.edn".source = ../config/clojure/deps.edn;
@@ -27,6 +26,7 @@
     iosevka-comfy.comfy-motion-duo
     jq
     kubectl
+    nixpkgs-fmt
     nodejs
     nodePackages.typescript-language-server
     nodePackages.vscode-json-languageserver
@@ -67,7 +67,7 @@
     emacs = {
       enable = true;
       extraConfig = builtins.readFile ../config/emacs/init.el +
-                    builtins.readFile ../config/emacs/lisp/utils.el;
+        builtins.readFile ../config/emacs/lisp/utils.el;
       extraPackages = epkgs: (with epkgs; [
         ace-window
         apheleia
@@ -167,7 +167,7 @@
         treesit-auto
         yaml-mode
         vterm
-	      fontaine
+        fontaine
         magit
         magit-todos
         marginalia