Fix typo in Blake2 function names

Fixes GitHub issue 2169.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2207)

doc/man3/EVP_DigestInit.pod

@@ -8,7 +8,7 @@ EVP_DigestInit, EVP_DigestFinal, EVP_MD_CTX_copy, EVP_MD_type,
 EVP_MD_pkey_type, EVP_MD_size, EVP_MD_block_size, EVP_MD_CTX_md, EVP_MD_CTX_size,
 EVP_MD_CTX_block_size, EVP_MD_CTX_type, EVP_md_null, EVP_md2, EVP_md5, EVP_sha1,
 EVP_sha224, EVP_sha256, EVP_sha384, EVP_sha512, EVP_mdc2,
-EVP_ripemd160, EVP_blake2b_512, EVP_blake2s_256, EVP_get_digestbyname,
+EVP_ripemd160, EVP_blake2b512, EVP_blake2s256, EVP_get_digestbyname,
 EVP_get_digestbynid, EVP_get_digestbyobj - EVP digest routines
 
 =head1 SYNOPSIS
@@ -48,8 +48,8 @@ EVP_get_digestbynid, EVP_get_digestbyobj - EVP digest routines
  const EVP_MD *EVP_sha1(void);
  const EVP_MD *EVP_mdc2(void);
  const EVP_MD *EVP_ripemd160(void);
- const EVP_MD *EVP_blake2b_512(void);
- const EVP_MD *EVP_blake2s_256(void);
+ const EVP_MD *EVP_blake2b512(void);
+ const EVP_MD *EVP_blake2s256(void);
 
  const EVP_MD *EVP_sha224(void);
  const EVP_MD *EVP_sha256(void);
@@ -127,8 +127,8 @@ are no longer linked this function is only retained for compatibility
 reasons.
 
 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
-EVP_sha384(), EVP_sha512(), EVP_mdc2(), EVP_ripemd160(), EVP_blake2b_512(), and
-EVP_blake2s_256() return B<EVP_MD> structures for the MD2, MD5, SHA1, SHA224,
+EVP_sha384(), EVP_sha512(), EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and
+EVP_blake2s256() return B<EVP_MD> structures for the MD2, MD5, SHA1, SHA224,
 SHA256, SHA384, SHA512, MDC2, RIPEMD160, BLAKE2b-512, and BLAKE2s-256 digest
 algorithms respectively.
 
@@ -153,7 +153,7 @@ EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and
 EVP_MD_CTX_block_size() return the digest or block size in bytes.
 
 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
-EVP_mdc2(), EVP_ripemd160(), EVP_blake2b_512(), and EVP_blake2s_256() return
+EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and EVP_blake2s256() return
 pointers to the corresponding EVP_MD structures.
 
 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()