[css-scroll-snap] Step-by-step de-duping of re-snapping requirements. Step 5: Fix up condition so that it includes layout changes; remove condition that the scroll container must have been previously snapped, since in proximity cases we need to re-evaluate on content changes regardless of previous snapping condition

Author: fantasai

css-scroll-snap/Overview.bs

@@ -335,9 +335,9 @@ Scroll Snapping Rules: the 'scroll-snap-type' property {#scroll-snap-type}
     in cases where it is longer than the screen.
 
     <!-- mandatory and proximity -->
-    If the content changes
-    such that the scroll container would no longer be <a>snapped</a>
+    If the content or layout of the document changes
     (e.g. content is added, moved, deleted, resized)
+    such that the content of the <a>snapport</a> changes,
     the UA must re-evaluate the resulting <a>scroll position</a>,
     and re-snap if required.
     If the <a>scroll container</a> was <a>snapped</a> before the content change