Correct the placement of the swapOut trigger to be in accordance with the documentation

The proposed documentation (#1859) says:

>Triggered when the new view has replaced the old view within the Region.

However `swapOut` is triggered before the described action has happened. We have to move
```javascript
this.triggerMethod('swapOut', this.currentView);
```
to be after
```javascript
this.attachHtml(view);
```

More info on #1866