[scroll-animations-1] Define animation-range-start|end with animation type (w3c#8426)

Author: cdoublev

scroll-animations-1/Overview.bs

@@ -780,7 +780,7 @@ spec: cssom-view-1; type: dfn;
 		Inherited: no
 		Percentages: relative to the specified [=named timeline range=]
 		Computed value: list, each item either the keyword ''animation-range-start/normal'' or a timeline range and progress percentage
-		Animatable: no
+		Animation type: not animatable
 	</pre>
 
 	Shifts the <a spec="web-animations-1">start time</a> of the animation
@@ -809,7 +809,7 @@ spec: cssom-view-1; type: dfn;
 		Inherited: no
 		Percentages: relative to the specified [=named timeline range=]
 		Computed value: list, each item either the keyword ''animation-range-end/normal'' or a timeline range and progress percentage
-		Animatable: no
+		Animation type: not animatable
 	</pre>
 
 	Shifts the <a spec="web-animations-1">end time</a> of the animation