doc: EventTarget and Event are available to user code since v15.0.0

PR-URL: https://github.com/nodejs/node/pull/37059
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/events.md

@@ -1148,8 +1148,6 @@ changes:
 
 The `EventTarget` and `Event` objects are a Node.js-specific implementation
 of the [`EventTarget` Web API][] that are exposed by some Node.js core APIs.
-Neither the `EventTarget` nor `Event` classes are available for end
-user code to create.
 
 ```js
 const target = new EventTarget();