[css-break-3] Define behavior for replaced elements #1904

The 'Applies to' line on break-inside doesn't seem to imply that it applies to block-level images, which it should. Mats's comment on this:

Fwiw, css-break-3 says for 'break-inside':
"Applies to: elements in the normal flow that establish formatting contexts, or that are block containers, table row groups, or table rows"
https://drafts.csswg.org/css-break/#propdef-break-inside

So according to that, 'break-inside' doesn't apply to images with display:block since they are not "containers" IMO.

CSS 2 is clearer that it does:
"Applies to: block-level elements (but see text)"
https://www.w3.org/TR/2011/REC-CSS2-20110607/page.html#page-break-props