nix: remove unused wsl mkSystem arg

flake.nix

···
       nixosConfigurations."alnitak-wsl" = mkSystem "alnitak-wsl" {
         system = "x86_64-linux";
         user = "alnitak";
-        wsl = true;
         hardware = wsl.nixosModules.wsl;
       };
 

nix/home-manager/home.nix

···
-{ darwin, wsl }:
-{ pkgs, lib, ... }: {
+{ darwin }:
+{ pkgs, lib, ... }:
+{
   programs.home-manager.enable = true;
 
   # This value determines the Home Manager release that your