[css-scroll-snap] Add issue about tie-breaking.

Author: tabatkins

css-scroll-snap/Overview.bs

@@ -841,6 +841,11 @@ Choosing Snap Positions {#choosing}
 
 		Issue: This would prevent space-travel effects. I think we should remove this.
 
+	Issue: Does tie-resolution need to be specified? Inertial and semantic scrolls are easy--
+	just choose the next one in the scroll direction--
+	but explicit scrolls don't have a direction.
+	Should we require defaulting to the start/end-most?
+
 <!--
 Group-based Snapping {#group}
 ========================