docs: fix discussion of axis letters in canned cycles
docs: fix discussion of axis letters in canned cycles

ArcEye/MK-Qt5,cdsteinkuehler/linuxcnc,kinsamanka/machinekit,araisrobo/machinekit,RunningLight/machinekit,araisrobo/linuxcnc,cdsteinkuehler/MachineKit,cdsteinkuehler/MachineKit,strahlex/machinekit,araisrobo/machinekit,mhaberler/machinekit,narogon/linuxcnc,ianmcmahon/linuxcnc-mirror,ikcalB/linuxcnc-mirror,RunningLight/machinekit,unseenlaser/linuxcnc,cdsteinkuehler/linuxcnc,bobvanderlinden/machinekit,bobvanderlinden/machinekit,EqAfrica/machinekit,bmwiedemann/linuxcnc-mirror,strahlex/machinekit,araisrobo/machinekit,cdsteinkuehler/linuxcnc,ArcEye/machinekit-testing,bobvanderlinden/machinekit,cnc-club/linuxcnc,bmwiedemann/linuxcnc-mirror,ArcEye/machinekit-testing,cnc-club/linuxcnc,aschiffler/linuxcnc,unseenlaser/machinekit,ArcEye/machinekit-testing,araisrobo/machinekit,jaguarcat79/ILC-with-LinuxCNC,EqAfrica/machinekit,araisrobo/linuxcnc,unseenlaser/machinekit,bmwiedemann/linuxcnc-mirror,bobvanderlinden/machinekit,jaguarcat79/ILC-with-LinuxCNC,araisrobo/machinekit,ianmcmahon/linuxcnc-mirror,Cid427/machinekit,mhaberler/machinekit,bmwiedemann/linuxcnc-mirror,cdsteinkuehler/MachineKit,RunningLight/machinekit,ikcalB/linuxcnc-mirror,aschiffler/linuxcnc,EqAfrica/machinekit,aschiffler/linuxcnc,cdsteinkuehler/MachineKit,kinsamanka/machinekit,narogon/linuxcnc,RunningLight/machinekit,unseenlaser/machinekit,mhaberler/machinekit,bobvanderlinden/machinekit,cnc-club/linuxcnc,ArcEye/machinekit-testing,araisrobo/machinekit,ArcEye/MK-Qt5,jaguarcat79/ILC-with-LinuxCNC,araisrobo/linuxcnc,kinsamanka/machinekit,kinsamanka/machinekit,ianmcmahon/linuxcnc-mirror,unseenlaser/linuxcnc,ikcalB/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,cdsteinkuehler/linuxcnc,bobvanderlinden/machinekit,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,cnc-club/linuxcnc,Cid427/machinekit,Cid427/machinekit,Cid427/machinekit,ArcEye/MK-Qt5,ianmcmahon/linuxcnc-mirror,ArcEye/MK-Qt5,kinsamanka/machinekit,bmwiedemann/linuxcnc-mirror,RunningLight/machinekit,EqAfrica/machinekit,ArcEye/MK-Qt5,mhaberler/machinekit,RunningLight/machinekit,unseenlaser/machinekit,bobvanderlinden/machinekit,mhaberler/machinekit,EqAfrica/machinekit,kinsamanka/machinekit,ArcEye/MK-Qt5,cnc-club/linuxcnc,cdsteinkuehler/MachineKit,narogon/linuxcnc,strahlex/machinekit,araisrobo/machinekit,strahlex/machinekit,strahlex/machinekit,araisrobo/linuxcnc,narogon/linuxcnc,bobvanderlinden/machinekit,ArcEye/machinekit-testing,bmwiedemann/linuxcnc-mirror,mhaberler/machinekit,ianmcmahon/linuxcnc-mirror,kinsamanka/machinekit,bmwiedemann/linuxcnc-mirror,ikcalB/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,narogon/linuxcnc,ArcEye/MK-Qt5,aschiffler/linuxcnc,cdsteinkuehler/linuxcnc,Cid427/machinekit,mhaberler/machinekit,mhaberler/machinekit,RunningLight/machinekit,kinsamanka/machinekit,Cid427/machinekit,ArcEye/machinekit-testing,unseenlaser/linuxcnc,Cid427/machinekit,araisrobo/linuxcnc,cnc-club/linuxcnc,unseenlaser/linuxcnc,jaguarcat79/ILC-with-LinuxCNC,araisrobo/machinekit,unseenlaser/machinekit,araisrobo/machinekit,unseenlaser/linuxcnc,ArcEye/MK-Qt5,RunningLight/machinekit,EqAfrica/machinekit,Cid427/machinekit,ArcEye/machinekit-testing,EqAfrica/machinekit,aschiffler/linuxcnc,unseenlaser/machinekit,ikcalB/linuxcnc-mirror,cdsteinkuehler/linuxcnc,unseenlaser/machinekit,cnc-club/linuxcnc,strahlex/machinekit,ArcEye/machinekit-testing,jaguarcat79/ILC-with-LinuxCNC,cdsteinkuehler/MachineKit,unseenlaser/machinekit,EqAfrica/machinekit,strahlex/machinekit