This package could use some typescript definitions

[HSchmale16]

I'm using this package in typescript project so I created some typescript definitions. I'm not quite sure how they all fit together, but this is what I added to my project to get typescript to compile it and work.

/// <reference types="jquery" />

interface JQuery<TElement = HTMLElement> extends Iterable<TElement> {
    highlightWithinTextarea(arg0: { highlight: { highlight: () => RegExp; className: string; }[]; });
    highlightWithinTextarea(arg0: string);
}
```