[css-display] Changes section should say table captions and cells are now flow-root

It's great that finally table-cell and table-caption have the flow-root internal display type.
(I already suggested the change 1.5 years ago in https://lists.w3.org/Archives/Public/www-style/2015Jul/0369.html)

But the Changes section is wrong, it says
> Switched table-caption and table-cell to use flow as their inner display type

Instead of
> Switched table-caption and table-cell to use flow-root as their inner display type

--Oriol