test: clarify confusion over "client" in comment

Fix perplexing comment. It's not that TLS "clients" don't support
'secureConnect', it's that client sockets created with `new TLSSocket`
(as opposed to `tls.connect()`) don't support that event.

PR-URL: #25508
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-tls-socket-default-options.js

@@ -54,8 +54,9 @@ function test(client, callback) {
       }));
     }));
 
-    // Client doesn't support the 'secureConnect' event, and doesn't error if
-    // authentication failed. Caller must explicitly check for failure.
+    // `new TLSSocket` doesn't support the 'secureConnect' event on client side,
+    // and doesn't error if authentication failed. Caller must explicitly check
+    // for failure.
     (new tls.TLSSocket(null, client)).connect(pair.server.server.address().port)
       .on('connect', common.mustCall(function() {
         this.end('hello');