[css-nav-1] Fix a link error

Author: Jihye Hong

css-nav-1/Overview.bs

@@ -500,7 +500,7 @@ the User Agent must run the steps described below:
 <div class=example id=focusAreas-visible>
     The following code shows how to get all the visible focusable elements in the current page using {{Element/focusableAreas()}}.
     If the method finds a <a>spatial navigation container</a>, it recursively finds focusable areas inside it.
-    However, as the {{FocusableAreasOptions/mode}} attribute of this method is set to <code>visible</code>,
+    However, as the {{FocusableAreasOption/mode}} attribute of this method is set to <code>visible</code>,
     the focusable element which isn’t inside the <a>scrollport</a> is excluded from the result.
 
     <pre><code highlight=markup>