Reviewed-by: NRichard Levitte <levitte@openssl.org>

L<foo|foo> is sub-optimal  If the xref is the same as the title,
which is what we do, then you only need L<foo>.  This fixes all
1457 occurrences in 349 files.  Approximately.  (And pod used to
need both.)
Reviewed-by: NRichard Levitte <levitte@openssl.org>

  [Chosen plaintext attack: R. Merkle, M. Hellman: "On the Security of
  Multiple Encryption", CACM 24 (1981) pp. 465-467, p. 776.

  Known plaintext angriff: P.C. van Oorschot, M. Wiener: "A
  known-plaintext attack on two-key triple encryption", EUROCRYPT '90.]