[css-position-3] Revert stickypos targeting back to using its offsetted position. #7930

Author: tabatkins

css-position-3/Overview.bs

@@ -685,15 +685,17 @@ Scroll Position of Sticky-Positioned Boxes
 
 	For the purposes of any operation targeting the scroll position
 	of a sticky positioned element (or one of its descendants),
-	the sticky positioned element must be considered to be positioned
-	at its initial (non-offsetted) position.
+	the sticky positioned element must be considered to be
+	at its offsetted position.
 
 
 		For example, if a user clicks a link targeting a [=sticky-positioned=] element,
-		even if the element's [=nearest scrollport=] is currently scrolled
+		if the element's [=nearest scrollport=] is currently scrolled
 		such that the [=sticky positioned=] element is offset from its initial position,
-		the [=scrollport=] will be scrolled back
-		so that the element's initial position is visible.
+		the [=scroll container=] will be scrolled back
+		only the minimum necessary to bring it into its desired position in the [=scrollport=]
+		(rather than scrolling all the way back
+		to target its original, non-offsetted position).