[css-nav-1] Include spatial-navigation-action:scroll in at-risk features

Author: frivoal

css-nav-1/Overview.bs

@@ -13,6 +13,7 @@ Abstract: This specification defines a general model for navigating the focus us
 At risk: {{getSpatialNavigationContainer()}}
 At risk: {{focusableAreas()}}
 At risk: 'spatial-navigation-contain'
+At risk: ''spatial-navigation-action: scroll''
 </pre>
 <pre class="anchors">
 spec: ui-events; urlPrefix: https://w3c.github.io/uievents/;