Feature request: Ability to use JSDOM or other dom library

[lajoiemedia]

It would be useful for nodejs and testing to have an option to use jsdom (or something else) as the provider of the dom.

It could be an option to html, e.g.

html({window: new JSDOM("").window})`<div>This is a test</div>`

Or else the htl library could export a setWindow function.

It would be a lot cleaner than what's being done here: https://github.com/observablehq/htl/blob/main/test/jsdom.js