Update wording in Overview.bs for clarity

Author: arichiv

css-pseudo-4/Overview.bs

@@ -1387,10 +1387,10 @@ Security Considerations for Highlighting</h3>
   can leak information about the contents of a user's dictionary
   (which can include the user's name and even includes the contents of their address book!)
   UAs that implement ''::spelling-error'' and ''::grammar-error''
-  must mitigate the following issues:
+  must mitigate the following attacks:
   <ul>
     <li>Pages attempting to directly read the styling of highlighted segments.</li>
-    <li>Pages attempting to track performance impacts of styling highlighted segments via programatic focusing and modification of text fields.</li>
+    <li>Pages attempting to track performance impacts of styling highlighted segments via programatic modification of text fields.</li>
   </ul>
 
 <h2 id="treelike">