[whatwg] [CSSWG][css-lists-3] Updated WD of CSS Lists Level 3

[fantasai]

The CSS WG has published an updated Working Draft of the
CSS Lists Module Level 3:

     https://www.w3.org/TR/css-lists-3/

The Lists module covers list-styling options such as changing counter styles
and marker position as well as automatic counters and numbering; Level 3
introduces
   * integration with the new counter styles in CSS Counter Styles L3
       https://www.w3.org/TR/css-counter-styles-3/
   * additional control over marker positioning
   * styling via the ::marker pseudo-element introduced in css-pseudo-4
   * the new counter-set property
   * the automagic 'list-item' counter, which allows referencing and manipulating
     the default list numbers

Note in particular that the 'list-item' counter interacts with the automatic
numbering features in the HTML spec. See
   https://www.w3.org/TR/css-lists-3/#list-item-counter

This is a significant and overdue redraft of Level 3: some experimental features
were dropped and the whole draft has been streamlined and tightened up, shifting
the draft from "please don't try to implement this" to "pretty reliable". However,
there are still some open issues against Chapter 4 (Automatic Numbering with
Counters), and we recommend continuing to use CSS2.1 as the definitive reference
for those features until L3 has been fully synchronized with it.

Significant changes are listed at:

   https://www.w3.org/TR/2019/WD-css-lists-3-20190425/#changes-20140320

Many thanks to Mozilla (Mats Palmgren, David Baron, and Emilio Cobos Álvarez)
for their detailed feedback this round.

Please review the draft, and send any comments to the www-style mailing list,
<www-style at w3.org>, prefixed with [css-lists-3] (as I did on this message) or
(preferably) file them in the GitHub repository at
   https://github.com/w3c/csswg-drafts/issues

For the CSS WG,
~fantasai