Switch ssl_parse_extensions to bool and Span.

This function is still a bit too C-like, but this is slightly better.

Change-Id: Id8931753c9b8a2445d12089af5391833a68c4901
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/43004
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
diff --git a/ssl/handshake_client.cc b/ssl/handshake_client.cc
index 1b7bb1b..5c800fb 100644
--- a/ssl/handshake_client.cc
+++ b/ssl/handshake_client.cc
@@ -358,8 +358,7 @@
 
   uint8_t alert = SSL_AD_DECODE_ERROR;
   if (!ssl_parse_extensions(&extensions, &alert, ext_types,
-                            OPENSSL_ARRAY_SIZE(ext_types),
-                            1 /* ignore unknown */)) {
+                            /*ignore_unknown=*/true)) {
     ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
     return false;
   }