HTMLElement type for SlickList `appendTo` prop

[Geloosa]

Hey @Jexordexan, could you please add support for HTMLElement in SlickList's appendTo prop? Query selector doesn't work in Shadow DOM, as there's no way to select an element inside it just by a string, but a call to shadow host element's shadowRoot is required: document.querySelector("shadowHostSelector").shadowRoot.querySelector("appendToSelector"). So it'd be nice to be able to pass an HTMLElement reference directly.