virtual: <VirtualList> needs listClass prop

[andraaspar]

Describe The Problem To Be Solved

I've found that when using <VirtualList> I could not style the list <div>. The styles I needed were:

display: flex;
flex-flow: column;
width: 100%;

Suggest A Solution

I think the right way is to let us have an optional listClass prop so we can style the list directly. This will not break any existing implementations. Like this:

<div
	class={props.listClass}
	style={{
		position: 'absolute',
		top: `${getFirstIdx() * props.rowHeight}px`,
	}}
>
	<For
		fallback={props.fallback}
		each={items().slice(getFirstIdx(), getLastIdx()) as any as T}
	>
		{props.children}
	</For>
</div>

[thetarnav]

First of many issues on virtual I expect, this is why I hate shipping jsx here. The user should be in full control of rendering.
Well listClass seems like an appropriate solution, if you submit a PR, I'll probably merge it.