[csswg-drafts] [css-grid] Positioned items don't participate in the grid container baseline

mrego has just created a new issue for 
https://github.com/w3c/csswg-drafts:

== [css-grid] Positioned items don't participate in the grid container
 baseline ==
The [grid container baseline 
definition](https://drafts.csswg.org/css-grid/#grid-baselines) talks 
generally about "grid items".

IMHO, it would be nice to explicitly exclude absolutely-positioned 
grid items, as they don't participate on the layout of the grid as 
stated in [10.1](https://drafts.csswg.org/css-grid/#abspos-items):
> does not contribute to the sizing of any grid tracks or affect the 
size/configuration of the grid in any way

Please view or discuss this issue at 
https://github.com/w3c/csswg-drafts/issues/639 using your GitHub 
account