Fix comment in sha2.h
An incorrect reference to was present.
Author: Daniel Gustafsson
Discussion:
#define PG_SHA512_DIGEST_LENGTH 64
#define PG_SHA512_DIGEST_STRING_LENGTH (PG_SHA512_DIGEST_LENGTH * 2 + 1)
-/* Context Structures for SHA-1/224/256/384/512 */
+/* Context Structures for SHA224/256/384/512 */
#ifdef USE_OPENSSL
typedef SHA256_CTX pg_sha256_ctx;
typedef SHA512_CTX pg_sha512_ctx;
