[css-inline-3] Fix definition of aligned subtree to use the layout bounds.

Author: fantasai

css-inline-3/Overview.bs

@@ -250,8 +250,6 @@ Layout Within Line Boxes</h3>
 		and boxes with line-box&ndash;relative 'vertical-align' values
 		are aligned with respect to the [=line box=].
 
-		Issue: Define interaction of line-relative alignment with 'leading-trim'.
-
 		Issue: Define what to do for top/bottom/center aligned boxes that are taller than the rest of the content.
 
 	Note: Empty [=inline boxes=] still have
@@ -856,12 +854,13 @@ Post-Alignment Shift: the 'baseline-shift' longhand</h4>
 			with the [=line-under=] edge of the [=line box=].
 	</dl>
 
-	The <dfn>aligned subtree</dfn> of an [=inline box=] contains that box
-	and the [=aligned subtrees=] of all children [=inline boxes=]
+	The <dfn>aligned subtree</dfn> of an [=inline box=] contains
+	the [=layout bounds=] of that box
+	and the [=aligned subtrees=] of all child [=inline boxes=]
 	whose computed 'alignment-baseline' value
 	is not itself a [=line-relative value=].
 	The [=line-over=] edge of the [=aligned subtree=]
-	is the highest [=over=] edge of the boxes in the subtree,
+	is the highest [=over=] edge of the [=layout bounds=] in the subtree,
 	and the [=line-under=] edge is analogously the lowest.
 
 <h5 class="no-toc" id="baseline-shift-svg-legacy">