[css-display] Fix block/inlinification rules to be more correct / less aggressive.

Author: tabatkins

css-display/Overview.bs

@@ -580,7 +580,11 @@ Automatic Box Type Transformations</h3>
 	(This has no effects on <a>display types</a> that generate no box at all,
 	such as ''display/none'' or ''display/contents''.)
 	Additionally, if the box originally had a [=layout-internal=] display type,
-	then its [=inner display type=] is set to ''flow''.
+	blockification converts its [=inner display type=] to ''flow''.
+
+	Issue: Should conversion of layout-internal display types also happen for inlinification?
+	If it does, should it change to ''flow'' or ''flow-root''?
+	If it doesn't, then anonymous-box fixup will handle things.
 
 	<div class='example'>
 		Some examples of this include:
@@ -596,6 +600,8 @@ Automatic Box Type Transformations</h3>
 	it recursively <a>inlinifies</a> all of its in-flow children,
 	so that no block-level descendants
 	break up the inline formatting context in which it participates.
+	If a ''block flow'' box is <a>inlinified</a>,
+	its <a>inner display type</a> is set to ''flow-root''.
 
 	The root element’s display type is always <a>blockified</a>.
 	Additionally, a 'display' of ''display/contents'' computes to ''block'' on the root element.