services.cron.enable: Remove misleading default

Elsewhere we set it to "mkDefault (allFiles != [])" to the default has
no effect.

Changed files
+1 -1
nixos
modules
services
scheduling
+1 -1
nixos/modules/services/scheduling/cron.nix
···
enable = mkOption {
type = types.bool;
-
default = true;
+
example = true;
description = "Whether to enable the Vixie cron daemon.";
};