[css-snappoints] guaranteed -> required

Author: ChumpChief

css-snappoints/Overview.bs

@@ -282,7 +282,7 @@ Scroll Snap Types: the 'scroll-snap-type' property {#scroll-snap-type}
 
         <dt><dfn>mandatory</dfn>
         <dd>
-            The <a>scroll container</a> is guaranteed to be <a>snapped</a> when there are no active scrolling operations.  If a reachable snap position exists then the scroll container must <a>snap</a> at the termination of a scroll.  If no reachable snap position exists then no <a>snapping</a> occurs.
+            The <a>scroll container</a> is required to be <a>snapped</a> when there are no active scrolling operations.  If a reachable snap position exists then the scroll container must <a>snap</a> at the termination of a scroll.  If no reachable snap position exists then no <a>snapping</a> occurs.
 
             If the content changes such that the scroll container would no longer be <a>snapped</a> (e.g. content is added, moved, deleted, resized) to the same snap position it was snapped to before the content change, the scroll container must be re-snapped.  If the same snap position it was snapped to before the content change still exists (e.g. its associated element was not deleted) and is reachable, the scroll container must be re-snapped to that same snap position after the content change.