Document undocumented public items

Perhaps depending on #605.
> Does there have to be an element that holds such events in jQuery? This shows otherwise. I didn't look into it, but, it seems that there is such a term as "custom event type"

Events in jQuery occur on elements, I'm not aware that they can occur in the absence of elements. Regarding the "custom event type," that refers to the following:

```javascript
$('body').on('my-awesome-event', function() {
    alert('Woo');
});
$('body').trigger('my-custom-event');
```

This will cause an alert to appear with the text "Woo".