[css-overflow-4] Bikeshed linking fix (#12810)

Author: andreubotella

css-overflow-4/Overview.bs

@@ -1051,7 +1051,7 @@ Handling of Excess Content: the 'continue' property</h3>
 			taken into account for the box's [=automatic block size=].
 
 			If the box is a [=multicol container=],
-			the behavior is the same as 'continue/auto'.
+			the behavior is the same as ''continue/auto''.
 
 		<dt><dfn>discard</dfn>
 		<dd>