MFH (r314554): fix date in previous commit

Also remove mention of SKEIN-512 since it is not available in 10.

MFH (r314528): update to reflect the state of SHA-1

MFC r300903: Implement SHA-512 truncated (224 and 256 bits)

MFC r292782: Replace sys/crypto/sha2/sha2.c with lib/libmd/sha512c.c

cperciva's libmd implementation is 5-30% faster
The same was done for SHA256 previously in r263218

Approved by: secteam

MFC r267667:
use .Mt to mark up email addresses consistently (part1)

PR: 191174
Submitted by: Franco Fichtner <franco at lastsummer.de>

MFC r266417 (bjk):

Assorted updates to md5.1

Note that the -c argument's parameter is compared against the digest of
the file, not the file. [1]

Update the "current time" parentheticals for notes about reversing
and colliding the hash functions. [1]

Some general mdoc updates.

PR: docs/188043 [1]
Submitted by: Jamie Landeg-Jones [1]

MFC r266417 (bjk):

Assorted updates to md5.1

Note that the -c argument's parameter is compared against the digest of
the file, not the file. [1]

Update the "current time" parentheticals for notes about reversing
and colliding the hash functions. [1]

Some general mdoc updates.

PR: docs/188043 [1]
Submitted by: Jamie Landeg-Jones [1]