Fix typos in SQL scripts of pgcrypto

Author: Gurjeet Singh
Discussion: https://postgr.es/m/CABwTF4U_5kEnH93PXZEuEsZHuoSSuBEOqC6pian8vDfLZSQJNA@mail.gmail.com

contrib/pgcrypto/expected/hmac-sha1.out

 --
--- HMAC-MD5
+-- HMAC-SHA1
 --
 SELECT encode(hmac(
 'Hi There',

contrib/pgcrypto/expected/pgp-decrypt.out

 --
--- pgp_descrypt tests
+-- pgp decrypt tests
 --
 --  Checking ciphers
 select pgp_sym_decrypt(dearmor('

contrib/pgcrypto/sql/hmac-sha1.sql

 --
--- HMAC-MD5
+-- HMAC-SHA1
 --
 
 SELECT encode(hmac(

contrib/pgcrypto/sql/pgp-decrypt.sql

 --
--- pgp_descrypt tests
+-- pgp decrypt tests
 --
 
 --  Checking ciphers