doc: discourage use of util.inherits; point to es6 extends

doc/api/events.md

@@ -27,27 +27,6 @@ The following example shows a simple `EventEmitter` instance with a single
 listener. The `eventEmitter.on()` method is used to register listeners, while
 the `eventEmitter.emit()` method is used to trigger the event.
 
-```js
-const EventEmitter = require('events');
-const util = require('util');
-
-function MyEmitter() {
-  EventEmitter.call(this);
-}
-util.inherits(MyEmitter, EventEmitter);
-
-const myEmitter = new MyEmitter();
-myEmitter.on('event', () => {
-  console.log('an event occurred!');
-});
-myEmitter.emit('event');
-```
-
-Any object can become an `EventEmitter` through inheritance. The example above
-uses the traditional Node.js style prototypical inheritance using
-the `util.inherits()` method. It is, however, possible to use ES6 classes as
-well:
-
 ```js
 const EventEmitter = require('events');