Fix documentation typo.

Change-Id: Ia060a9f8c30ea7446ddffcc2221a8f5a37f14d8c
Reviewed-on: https://boringssl-review.googlesource.com/6415
Reviewed-by: Adam Langley <agl@google.com>

include/openssl/ssl.h

diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 00abcde..2acf455 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -396,7 +396,7 @@
  * |SSL_do_handshake|. */
 #define SSL_ERROR_WANT_READ 2
 
-/* SSL_ERROR_WANT_READ indicates the operation failed attempting to write to
+/* SSL_ERROR_WANT_WRITE indicates the operation failed attempting to write to
  * the transport. The caller may retry the operation when the transport is ready
  * for writing. */
 #define SSL_ERROR_WANT_WRITE 3