Add support for :has() pseudo-selector

Here's an example that functions in a browser DOM:
```js
const text = `
<div>
  <li>
  <p class='example'>text</p>
  </li>
  <li>
  <p>text</p>
  </li>
</div>`
const parser = new DOMParser().parseFromString(text, "text/html")!;
const itemWithExample= parser.querySelector("li:has(.example)");
assert(itemWithExample);
```