MFC r327514,r327521,r327614,r327615,r327616,r327623:

morse(6): several improvements

• add ñ, ', and _
• remove lint support
• add missing header for ioctl
• fix two typod
• Use -r for "reverse" mode and to match DragonFlyBSD.
• Move defines around to clear up logic
• use errx instead of fprintf and exit
• Use copyright comment header
• Make it easier to compile on !FreeBSD
• Diff reduction against DragonFlyBSD
• bump Dd
• use 'r' instead of 'D' from the original submission

PR: 35109