[css-lists] Clarify whether ::before and ::after pseudo-elements can be list-items and increment the list-item counter. #3766
Description
The following renders differently across browsers:
<!doctype html>
<style>
li::before, li::after { content: "Before"; display: list-item; }
li::after { content: "After"; }
</style>
<ol>
<li>FooList item is defined in https://drafts.csswg.org/css-lists/#list-item / https://drafts.csswg.org/css-lists/#declaring-a-list-item, but it doesn't clarify if ::before or ::after are supposed to increment the list item counter.