[css-scoping] markup fix

Author: tabatkins

css-scoping/Overview.bs

@@ -400,7 +400,7 @@ Selecting Into the Dark: the ''::shadow'' pseudo-element</h4>
 
 	If an element has at least one <a>shadow tree</a>,
 	the <dfn>::shadow</dfn> pseudo-element matches the <a>shadow roots</a> themselves.
-	In HTML, the <a>shadow root</a> is represented by <a interface>ShadowRoot</a> objects.
+	In HTML, the <a>shadow root</a> is represented by {{ShadowRoot}} objects.
 
 	The ''::shadow'' pseudo-element must not generate boxes,
 	unless specified otherwise in another specification.