nixos-generate-config: add programs options examples

nixos/modules/installer/tools/nixos-generate-config.pl

@@ -583,9 +583,15 @@ $bootLoaderConfig
   # List packages installed in system profile. To search by name, run:
   # \$ nix-env -qaP | grep wget
   # environment.systemPackages = with pkgs; [
-  #   wget
+  #   wget vim
   # ];
 
+  # Some programs need SUID wrappers, can be configured further or are
+  # started in user sessions.
+  # programs.bash.enableCompletion = true;
+  # programs.mtr.enable = true;
+  # programs.gnupg.agent = { enable = true; enableSSHSupport = true; };
+
   # List services that you want to enable:
 
   # Enable the OpenSSH daemon.