lib.host: Minor cleanup and formatting

lib/host.nix

@@ -1,4 +1,14 @@
-{ pkgs, nixpkgs, nixos-unstable, unstable, home-manager, system, mkHomeRole, mkSysRole, mkUser, ... }:
+{ pkgs
+, nixpkgs
+, nixos-unstable
+, unstable
+, home-manager
+, system
+, mkHomeRole
+, mkSysRole
+, mkUser
+, ...
+}:
 
 {
   mkHost = { name, users, roles ? [ ], imports ? [ ] }:
@@ -22,19 +32,28 @@
             (mkSysRole "common")
             (mkSysRole "acme")
           ];
+
           nixpkgs = { inherit pkgs; };
 
-          nix.nixPath = [ "nixpkgs=${nixpkgs}" "unstable=${nixos-unstable}" ];
+          nix = {
-          nix.registry.nixpkgs.flake = nixpkgs;
+            nixPath = [
-          nix.registry.unstable.flake = nixos-unstable;
+              "nixpkgs=${nixpkgs}"
+              "unstable=${nixos-unstable}"
+            ];
+            registry = {
+              nixpkgs.flake = nixpkgs;
+              unstable.flake = nixos-unstable;
+            };
+          };
 
           users.users.root = { shell = pkgs.zsh; };
 
           home-manager = {
-            users.root.imports = [ (mkHomeRole "common") ];
+            users.root.imports = pkgs.lib.singleton (mkHomeRole "common");
             extraSpecialArgs.unstable = unstable;
             useGlobalPkgs = true;
           };
+
           system.stateVersion = "22.11";
         }