provide quasiquoters that produce `Element`s or `[Node]`

Right now, all of the quasiquoters produce `Document`s.

It would be nice to have quasiquoters that produce both [`Element`s](https://hackage.haskell.org/package/xml-conduit-1.4.0.3/docs/Text-XML.html#t:Element) and [`[Node]`](https://hackage.haskell.org/package/xml-conduit-1.4.0.3/docs/Text-XML.html#t:Node).