[css-grid-1] Min track sizes can't be flex values anymore. w3c#3568

Author: fantasai

css-grid-1/Overview.bs

@@ -3833,7 +3833,6 @@ Initialize Track Sizes</h3>
 			as they're treated as ''auto''.
 
 		<dt>An <a>intrinsic sizing function</a>
-		<dt>A <a>flexible sizing function</a>
 		<dd>
 			Use an initial <a>base size</a> of zero.
 	</dl>