[css3-multicol] Applies to block containers

Hi,

The columns, column-width and column-count properties all have the same 
"Applies to" line:

> non-replaced block-level elements (except table elements), table
> cells, and inline-block elements

This should really be "block container" instead of an inclusive list of 
the block containers that exist in CSS 2.1.

Block-level flex containers are in the list above but are not block 
containers; I believe multicol should not apply to them. Flex items are 
not in the list, but are block containers; multicol should apply.

"Block container" is the general term that stays relevant as we keep 
adding new layout modes.


Except that elements that multicol are not block containers anymore. So 
I guess that the properties really apply to "elements that would 
otherwise have been block containers." But that’s awkward. "Applies to: 
block containers" is probably a good enough approximation.

-- 
Simon Sapin