doc: update return types for eventNames method in EventEmitter

PR-URL: #58083
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: LiviaMedeiros <livia@cirno.name>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

Author: y-hsgw

doc/api/events.md

@@ -603,10 +603,10 @@ myEmitter.emit('event', 1, 2, 3, 4, 5);
 added: v6.0.0
 -->
 
-* Returns: {Array}
+* Returns: {string\[]|symbol\[]}
 
 Returns an array listing the events for which the emitter has registered
-listeners. The values in the array are strings or `Symbol`s.
+listeners.
 
 ```mjs
 import { EventEmitter } from 'node:events';

lib/events.js

@@ -871,7 +871,7 @@ function listenerCount(type, listener) {
 /**
  * Returns an array listing the events for which
  * the emitter has registered listeners.
- * @returns {any[]}
+ * @returns {(string | symbol)[]}
  */
 EventEmitter.prototype.eventNames = function eventNames() {
   return this._eventsCount > 0 ? ReflectOwnKeys(this._events) : [];