[css-position-3] Remove duplicate/contradictory animation line from 'position' propdef. w3c#6846

Author: tabatkins

css-position-3/Overview.bs

@@ -203,7 +203,6 @@ Choosing A Positioning Scheme: 'position' property</h2>
 	Initial: static
 	Applies to: all elements except table-column-group and table-column
 	Inherited: no
-	Animatable: no
 	Percentages: N/A
 	Computed value: specified keyword
 	Animation type: discrete