[CSSWG][css-pseudo-4] Updated WD of CSS Pseudo-elements Level 4

The CSS WG has published an updated Working Draft of the
CSS Pseudo-elements Module Level 4:

   https://www.w3.org/TR/css-pseudo-4/

This CSS module defines pseudo-elements, abstract elements that represent
portions of the CSS render tree that can be selected and styled.

This somewhat-overdue publication includes the new ::marker pseudo-class,
as well as ::inactive-selection. Changes are listed at
   https://www.w3.org/TR/2016/WD-css-pseudo-4-20160607/#changes

Please review the draft, and either file comments in the CSSWG GitHub repo:
   https://github.com/w3c/csswg-drafts/issues
or mail them to <[email protected]>, prefixed with [css-pseudo-4]
(as I did on this message).

For the CSS WG,
~fantasai