doc: fix typo in http2stream.close param default

PR-URL: nodejs#18166
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

doc/api/http2.md

@@ -919,7 +919,7 @@ added: v8.4.0
 -->
 
 * code {number} Unsigned 32-bit integer identifying the error code. **Default:**
-  `http2.constant.NGHTTP2_NO_ERROR` (`0x00`)
+  `http2.constants.NGHTTP2_NO_ERROR` (`0x00`)
 * `callback` {Function} An optional function registered to listen for the
   `'close'` event.
 * Returns: {undefined}