waybar: fix slow service stop (#1852)

Set the systemd user service to use "mixed" killmode, which lets waybar
stop its module scripts. This fixes issues where waybar blocks shutdown
until systemd sends a SIGKILL to waybar child processes.

modules/programs/waybar.nix

@@ -378,6 +378,7 @@ in {
           ExecStart = "${cfg.package}/bin/waybar";
           Restart = "always";
           RestartSec = "1sec";
+          KillMode = "mixed";
         };
 
         Install = { WantedBy = [ "graphical-session.target" ]; };

tests/modules/programs/waybar/systemd-with-graphical-session-target.service

@@ -4,6 +4,7 @@ WantedBy=graphical-session.target
 [Service]
 BusName=fr.arouillard.waybar
 ExecStart=@waybar@/bin/waybar
+KillMode=mixed
 Restart=always
 RestartSec=1sec
 Type=dbus