[css-align] bikeshed fix

Author: tabatkins

css-align/Overview.bs

@@ -20,6 +20,10 @@ Ignored Terms: table cell, stretch, scrollable overflow region
 At Risk: ''last-baseline'', the <<overflow-position>> keywords, the scrollable-area safety trigger into ''safe'' mode when no <<overflow-position>> is specified
 </pre>
 
+<pre class=link-defaults>
+spec:css-overflow-3; type:dfn; text:scroll container
+</pre>
+
 <style type="text/css">
 .issue th:first-child { text-align: left !important; }
 [rowspan] > img { float: right; }