[css-overflow-3] Define that clip computes to hidden when the other axis is neither visible nor clip. #1971

Author: fantasai

css-overflow-3/Overview.bs

@@ -277,7 +277,7 @@ Scrollable Overflow: the 'overflow-x', 'overflow-y', and 'overflow' properties</
 		Inherited: no
 		Percentages: N/A
 		Media: visual
-		Computed value: as specified, except with ''visible'' computing to ''auto'' if one of 'overflow-x' or 'overflow-y' is not ''visible''
+		Computed value: as specified, except with ''visible''/''clip'' computing to ''auto''/''hidden'' (respectively) if one of 'overflow-x' or 'overflow-y' is neither ''visible'' nor ''clip''
 		Animatable: no
 	</pre>