[devShell] add tokei

devShells/default/default.nix

···
 }:
 pkgs.mkShellNoCC {
   packages = [
+    # keep-sorted start
     pkgs.deadnix
     pkgs.just
     pkgs.nil
+    pkgs.nix-output-monitor
     pkgs.nix-tree
     pkgs.nixd
-    pkgs.nix-output-monitor
     pkgs.nixfmt-rfc-style
+    pkgs.nixos-rebuild-ng
+    pkgs.nvd
     pkgs.statix
-    pkgs.nvd
-    pkgs.nixos-rebuild-ng
+    pkgs.tokei
+    # keep-sorted endd
   ];
 }