Fix the data passed in page:done event

https://github.com/igor-alexandrov/wiselinks/pull/62 breaks what the [readme](https://github.com/igor-alexandrov/wiselinks#javascript-events) says about `data`:
```
page:done ($target, status, url, data)

Event is triggered if the request succeeds.

    $target – jQuery object that was updated with the request;

    status – a string describing the status;

    url – url of the request;

    data – content of the request;
```
Now it always passes the target DOM, but I expect a full document when it is returned by request from server/browser cache to do some custom update