currentElement and DocumentFragment

[sparhami]

If a DocumentFragment is being patched and currentElement is called at the root, then it will actually return a Node and not an Element.

I'm not sure if an assert should be added or if it should be currentNode instead. It doesn't seem like a good idea to expose the node being patched from inside, so an assert making sure that it isn't called at the root might be a good idea.

[jridgewell]

This is actually one of my needs for currentElement. But let me see if I can get around that with the new skip.

[sparhami]

If this functionality is still needed, perhaps we should just add an assert that the current parent is in fact an Element rather than just casting it.