[css-sizing-3] Genericize the properties slightly, so flex-basis properly falls under it. #6822

Author: tabatkins

css-sizing-3/Overview.bs

@@ -1161,7 +1161,9 @@ Intrinsic Contributions of Percentage-Sized Boxes</h4>
 	when calculating the used sizes and positions of the containing block’s <em>contents</em>:
 
 	* If the cyclic dependency was introduced due to
-		a 'block-size' or 'max-block-size' on the containing block
+		a [=block-axis=] size other than a [=minimum size=] on the containing block
+		(i.e. a 'block-size' or 'max-block-size' in most layout modes,
+		or a 'flex-basis' in [=flex layout=])
 		that causes it to depend on the size of its contents,
 		the box’s percentage is not resolved and instead <a>behaves as auto</a>.