While there, remove .Tn from man pages.
Also remove an obsolete comment about the 80386.
MFC after: 1 week
Sponsored by: Klara, Inc.
Reviewed by: kevans, allanjude
Differential Revision: https://reviews.freebsd.org/D38373
Connect it to userland (libmd, libcrypt, sbin/md5) and kernel (crypto.ko)
Support for skein as a ZFS checksum algorithm was introduced in r289422
but is disconnected because FreeBSD lacked a Skein implementation.
A further commit will enable it in ZFS.
Reviewed by: cem
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D6166