[css-sizing-3] Adjust definition of cyclic percentage per #3010

Author: fantasai

css-sizing-3/Overview.bs

@@ -1005,14 +1005,13 @@ Intrinsic Contributions</h3>
 Intrinsic Contributions of Percentage-Sized Boxes</h4>
 
 	Sometimes the size of a percentage-sized box’s <a>containing block</a>
-	depends on the intrinsic size contribution of the box itself,
+	depends on the [=intrinsic size contribution=] of the box itself,
 	creating a cyclic dependency.
 	When calculating the <a>intrinsic size contribution</a> of such a box
 	(including any calculations for a content-based <a>automatic minimum size</a>),
-	a <dfn export>cyclic percentage</dfn>--
-	that is,
-	a percentage value that would resolve against a containing block size
-	which itself depends on that percentage--
+	a percentage value that resolves against a size
+	in the same axis as the [=intrinsic size contribution=]
+	(a <dfn>cyclic percentage</dfn>)
 	is resolved specially:
 
 	<ol type=a>