Added note on ripemd160 copyright.

Rev: nettle/nettle.texinfo:1.27

nettle.texinfo

@@ -187,8 +187,13 @@ The implementation of the MD5 message digest is written by Colin Plumb.
 It has been hacked some more by Andrew Kuchling and @value{AUTHOR}.
 Released into the public domain.
 
+@item RIPMED160
+The implementation of RIPEMD160 message digest is based on the code in
+libgcrypt, copyright owned by the Free Software Foundation. Ported to
+Nettle by Andres Mejia. Released under the LGPL.
+
 @item SERPENT
-The implementation of the SERPENT is based on the code in libgcrypt,
+The implementation of the SERPENT cipher is based on the code in libgcrypt,
 copyright owned by the Free Software Foundation. Adapted to Nettle by
 Simon Josefsson and heavily modified by Niels Möller. Assembly for
 x86_64 by Niels Möller. Released under the LGPL.