[css-sizing-3] Export 'cyclic percentage'.

Author: tabatkins

css-sizing-3/Overview.bs

@@ -989,7 +989,7 @@ Extrinsic Size Determination</h2>
 	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>cyclic percentage</dfn>--
+	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--
@@ -1264,7 +1264,7 @@ Changes</h2>
 	<ul>
 		<li>...
 		<li>Switched default sizing of an object with an intrinsic aspect ratio to use the ICB size instead of 300px&times;150px.
-			(<a href="https://github.com/w3c/csswg-drafts/issues/4218">Issue 4218</a>)	
+			(<a href="https://github.com/w3c/csswg-drafts/issues/4218">Issue 4218</a>)
 	</ul>
 
 	<p>