Can't useRef to get reference to DOM element

[Ian Luca]

Example:

const myRef = useRef(null);
useEffect(() => {
  myRef.current.requestFullscreen();
}, []);
html`<div ref=${myRef}></div>`;

Current behaviour:

Uncaught TypeError: Cannot read property 'requestFullscreen' of undefined

Expected behaviour:

Element enters fullscreen if the browser supports it, some other error otherwise.

Based on this answer I have found a way to make it work. Tested with virtual components! (which seems to be the most difficult part, so normal component should be fine).

Would you accept a PR to address this?