Update auto-releasing wake lock examples

Fix #300

index.html

@@ -620,16 +620,20 @@ <h3>
           <dfn>Auto-releasing wake locks</dfn>
         </h3>
         <p>
-          A user agent may <a>release a wake lock</a> at any time it:
+          A user agent may <a>release a wake lock</a> at any time, for example,
+          when:
         </p>
         <ul>
-          <li>Detects abnormal operation: such as infinite loops and tasks
+          <li>It detects abnormal operation: such as infinite loops and tasks
           exceeding imposed time limits (if any).
           </li>
           <li>Battery is considered low and discharging.
           </li>
           <li>The user turns on some kind of device power conservation mode.
           </li>
+          <li>The operating system is configured to dim or turn off the screen
+          based on the user presence state.
+          </li>
         </ul>
       </section>
       <section>