per issue 420 - fixing dismissible

Author: Andrew Kirkpatrick

guidelines/sc/21/content-on-hover-or-focus.html

@@ -10,7 +10,7 @@ <h4>Content on Hover or Focus</h4>
 
   <dl>
 
-    <dt>Dismissable</dt>
+    <dt>Dismissible</dt>
     <dd>A <a>mechanism</a> is available to dismiss the additional content without moving pointer hover or keyboard focus, unless the additional content communicates an <a>input error</a> or does not obscure or replace other content;</dd>
 
     <dt>Hoverable</dt>