nixos/tmux: add related package

This is a trivial example of `relatedPackages` option usage.

Changed files
+6 -1
nixos
modules
programs
+6 -1
nixos/modules/programs/tmux.nix
···
options = {
programs.tmux = {
-
enable = mkEnableOption "<command>tmux</command> - a <command>screen</command> replacement.";
+
enable = mkOption {
+
type = types.bool;
+
default = false;
+
description = "Whenever to configure <command>tmux</command> system-wide.";
+
relatedPackages = [ "tmux" ];
+
};
aggressiveResize = mkOption {
default = false;