Add scroll-anchor suppression trigger for changes to computed value of overflow-anchor

Author: chrishtr

css-scroll-anchoring-1/Overview.bs

@@ -222,6 +222,7 @@ These triggers are:
 	* 'width', 'height', 'min-width', 'max-width', 'min-height', or 'max-height'
 	* 'position'
 	* 'transform'
+	* 'overflow-anchor'
 
 * Any change to the computed value of the 'position' property
 	on any element within the scrollable element (or document),