refactor(nixos): inline module enable conditions

configs/nixos/modules/desktop/apps/alacritty.nix

@@ -6,14 +6,13 @@
 }:
 # Alacritty as the desktop terminal.
 let
-  cfg = config.modules.desktop.apps.alacritty; # NOLINT(let_order)
   user = config.user.name;
 in
 {
   options.modules.desktop.apps.alacritty.enable =
     lib.mkEnableOption "Alacritty as the desktop terminal";
 
-  config = lib.mkIf cfg.enable {
+  config = lib.mkIf config.modules.desktop.apps.alacritty.enable {
     home-manager.users.${user}.home.packages = [ pkgs.alacritty ];
   };
 }