feat: Add generic overloads for Find and WaitFor methods to support s…

[linkdotnet]

Add Find<TComponent, TElement> as a convenient way of having TElement returned.

So folks don't have to do:

var element = cut.Find("a") as IHtmlAnchorElement;

element.ShouldNotBeNull();
element.AssertWhatever();

Of course - if they are sure they could use:

var element = (IHtmAnchorElement)cut.Find("a");

And would get an exception. The new API would help here a bit better with a proper message inside the exception. That is also why I did not use Nodes.QuerySelector<TElement> internally, so that we can distinguish between:

1. The css selector doesn't yield any element in the DOM
2. There is an element, but the type is different