This change is made for two reasons:
1. If `toString config.restartTriggers` containes `\n`, systemd unit
file will be ill-formed.
2. This change can limit length of the trigger, although it doesn't
matter in most cases.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at https://nixos.org/nixos and in the manual in doc/manual.