allow selector array for chaining selectors

[gajus]

Consider the following example:

selector: [
  '.movie[data-id="1"]',
  '.item-list a[href^="/reservation"]'
]

We want to ensure .movie[data-id="1"] selector matches 1 element, then we want to select the descending .item-list a[href^="/reservation"] element.

This is different from .movie[data-id="1"] .item-list a[href^="/reservation"]. The latter would match:

<div data-id="1"></div>
<div data-id="1">
  <div class="list-item">
    <a href="/reservation"></a>
  </div>
</div>

The former would not.

An alternative is to allow use of the quantifier expression anywhere in the selector, e.g.

.movie[data-id="1"] {1}[0] .item-list a[href^="/reservation"]