[scroll-animations-1] Clarify that animation-range can expand the range. #8578

Author: fantasai

scroll-animations-1/Overview.bs

@@ -1170,6 +1170,10 @@ spec: cssom-view-1; type: dfn;
 	are set within this restricted range,
 	further reducing the time available for ''animation-duration/auto'' durations
 	and ''animation-iteration-count/infinite'' iterations.
+
+	Note: 'animation-range' can expand the [=attachment range=]
+	as well as constrict it.
+
 	Any frames positioned outside the [=attachment range=]
 	are used for interpolation as needed,
 	but are outside the [=active interval=]