grub, syslinux: use id 'rescue' in 33live-rescue.cfg as in 80rescue.cfg

features.in/grub/cfg.in/33live-rescue.cfg

-menuentry $"Rescue LiveCD" --id 'live_rescue' {
+menuentry $"Rescue LiveCD" --id 'rescue' {
   savedefault
   echo $"Loading Linux vmlinuz$KFLAVOUR ..."
   linux /boot/vmlinuz$KFLAVOUR fastboot live @initrd_bootargs@ @stagename@=live systemd.unit=live-rescue.target ramdisk_size=@live_size@ nosplash vga=@bootvga@ @rescue_bootargs@ lang=$lang lowmem

features.in/syslinux/cfg.in/33live-rescue.cfg

-label live_rescue
+label rescue
   menu label ^Rescue LiveCD
   kernel /boot/vmlinuz
   append initrd=/boot/@initrd@ fastboot live @initrd_bootargs@ @stagename@=live systemd.unit=live-rescue.target ramdisk_size=@live_size@ nosplash showopts vga=@bootvga@ @rescue_bootargs@ lowmem