Clarify that X25519 also supports EVP_PKEY_new_raw_private_key, etc

Fixed: 605
Change-Id: Id2b7d0221c3e43c102ce77c800f7ab65c74e0582
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/59625
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
diff --git a/include/openssl/evp.h b/include/openssl/evp.h
index 00ae4f5..f69cf75 100644
--- a/include/openssl/evp.h
+++ b/include/openssl/evp.h
@@ -239,9 +239,9 @@
 // Raw keys
 //
 // Some keys types support a "raw" serialization. Currently the only supported
-// raw format is Ed25519, where the public key and private key formats are those
-// specified in RFC 8032. Note the RFC 8032 private key format is the 32-byte
-// prefix of |ED25519_sign|'s 64-byte private key.
+// raw formats are X25519 and Ed25519, where the formats are those specified in
+// RFC 7748 and RFC 8032, respectively. Note the RFC 8032 private key format is
+// the 32-byte prefix of |ED25519_sign|'s 64-byte private key.
 
 // EVP_PKEY_new_raw_private_key returns a newly allocated |EVP_PKEY| wrapping a
 // private key of the specified type. It returns one on success and zero on