udevadm-control: fix error message

Extracted from #25523 by Lennart.

Author: dtardon

src/udev/udevadm-control.c

@@ -142,7 +142,7 @@ int control_main(int argc, char *argv[], void *userdata) {
 
                         r = safe_atou(optarg, &i);
                         if (r < 0)
-                                return log_error_errno(r, "Failed to parse maximum number of events '%s': %m", optarg);
+                                return log_error_errno(r, "Failed to parse maximum number of children '%s': %m", optarg);
 
                         r = udev_ctrl_send_set_children_max(uctrl, i);
                         if (r == -ENOANO)