flake.nix: drop desc argument for runVM function

The current runVM function gets called only with a module and without a desc,
resulting in an error when running `nix flake show` or similar
commands.

This commit drops the `desc` argument to `runVM` and gets rid of that problem.

flake.nix

@@ -101,7 +101,7 @@
     formatter = forAllPlatforms (pkgs: pkgs.alejandra);
 
     apps = forBuildablePlatforms (pkgs: let
-      runVM = module: desc: let
+      runVM = module: let
         vm = import ./nix/vm/create.nix {
           inherit (pkgs.stdenv.hostPlatform) system;
           inherit module nixpkgs;