power management: restart post-resume.target on resume

Trigger a restart of the post-resume.target on resume.
That allows other systemd services to receive the restart signal
after resume by becoming 'partOf' the post-resume.target.

nixos/modules/config/power-management.nix

···
         after = [ "suspend.target" "hibernate.target" "hybrid-sleep.target" ];
         script =
           ''
+            ${config.systemd.package}/bin/systemctl try-restart post-resume.target
             ${cfg.resumeCommands}
             ${cfg.powerUpCommands}
           '';