Update references to RFC 7905.

Change-Id: I6ef23a23da3957eccbe6cd03727b9a9f367f6ef0
Reviewed-on: https://boringssl-review.googlesource.com/8470
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/tls1.h b/include/openssl/tls1.h
index d195940..973ea1c 100644
--- a/include/openssl/tls1.h
+++ b/include/openssl/tls1.h
@@ -432,6 +432,7 @@
 #define TLS1_CK_ECDHE_RSA_CHACHA20_POLY1305_OLD 0x0300CC13
 #define TLS1_CK_ECDHE_ECDSA_CHACHA20_POLY1305_OLD 0x0300CC14
 
+/* ChaCha20-Poly1305 cipher suites from RFC 7905. */
 #define TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 0x0300CCA8
 #define TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 0x0300CCA9
 #define TLS1_CK_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256 0x0300CCAC