[css-grid-1] Clarify animation type of grid-template-rows/columns. w3c#3201

Author: fantasai

css-grid-1/Overview.bs

@@ -1374,7 +1374,7 @@ Explicit Track Sizing: the 'grid-template-rows' and 'grid-template-columns' prop
 	Inherited: no
 	Percentages: refer to corresponding dimension of the content area
 	Computed value: the keyword ''grid-template-columns/none'' or a [=computed track list=]
-	Animation type: by computed value type
+	Animation type: if the list lengths match, by computed value type per item in the [=computed track list=]; discrete otherwise
 	</pre>
 
 	These properties specify,
@@ -4572,6 +4572,11 @@ Clarifications</h4>
 		<li id="change-2017-inner-outer">
 			Ensure that track sizes remain floored at zero during intrinsic sizing.
 			(<a href="https://github.com/w3c/csswg-drafts/issues/2655">Issue 2655</a>)
+		<li id="change-2017-animation">
+			More clearly defined computed value and animation type lines of each property,
+			particularly 'grid-template-rows' and 'grid-template-columns'.
+			(<a href="https://github.com/w3c/csswg-drafts/pull/3198">PR 3198</a>,
+			 <a href="https://github.com/w3c/csswg-drafts/issues/3201">Issue 3201</a>)
 	</ul>
 
 <h3 id="changes-2016">