[css-multicol-1] Define column-count with animation type (w3c#8418)

Author: cdoublev

css-multicol-1/Overview.bs

@@ -532,7 +532,7 @@ The Number and Width of Columns</h2>
 	Inherited: no
 	Percentages: N/A
 	Computed value: specified value
-	Animatable: by computed value
+	Animation Type: by computed value
 	</pre>
 
 	This property describes the number of columns of a [=multicol container=].