@hideconstructor doesn't work on ES6 classes

This never works:

```javascript
/**
* Lorem ipsum
* @hideconstructor
*/
export class EventDispatcher
{
constructor(initializer, finalizer) {}
}
```

This doesn't work when using `--document-exported`:

```javascript
/**
* Lorem ipsum
*/
export class EventDispatcher
{
/* @hideconstructor **/
constructor(initializer, finalizer) {}
}
```

* What version of documentation.js are you using?: 13.1.1
* How are you running documentation.js (on the CLI, Node.js API, Grunt, other?): CLI