[css-align] Resolve some scrolling mechanism conflicts in favor of latest CSS2.1 errata; mark as issue.

Author: fantasai

css-align/Overview.bs

@@ -1465,9 +1465,6 @@ Determining the Baselines of a Box</h2>
 			whichever comes first (last).
 			If there is no such line box or child,
 			then the block container has no baselines.
-			For the purposes of finding the baselines,
-			in-flow boxes with a scrolling mechanisms (see the 'overflow' property)
-			must be considered as if scrolled to their origin (final) position.
 
 			A block container has no block-axis baselines.
 
@@ -1540,9 +1537,12 @@ Determining the Baselines of a Box</h2>
 		Maybe these things are wrong?
 		CSS 2.1 is really weird about baseline alignment.
 
-	For boxes with non-''visible'' 'overflow',
-	if a baseline is past the box's margin edge on the opposite side
-	when the box is scrolled to its initial position,
+	For the purposes of finding the baselines of a box,
+	it and all its in-flow descendants with a scrolling mechanism (see the 'overflow' property)
+	must be considered as if scrolled to their origin.
+	Furthermore, if, in the case of a box with non-''visible'' overflow,
+	the resulting position of a first (last) baseline
+	is past a box's end (start) margin edge,
 	its position is clamped to that margin edge.
 	That is, when assuming the initial scroll position,
 	if a box's first baseline is past its end margin edge
@@ -1551,6 +1551,8 @@ Determining the Baselines of a Box</h2>
 	so that such a box's baseline
 	is never outside its margin edges.
 
+	ISSUE: This reflects the latest CSS2.1 errata, however see also discussion of an <a href="https://github.com/w3c/csswg-drafts/issues/766">alternate solution</a> that was previously drafted here.
+
 <h3 id='baseline-terms'>
 Baseline Alignment Terminology</h3>