Remove duplicated word. (#402)

instructions.html

@@ -26,7 +26,7 @@ <h1 class="section-header">Speedometer 3 General Instructions</h1>
                             <li>Restart the browser and close all other tabs and windows.</li>
                             <li>Keep the Speedometer page focused and do not interact with the device while running the benchmark.</li>
                             <li>Keep your battery-powered device plugged into a charger.</li>
-                            <li>Some devices might need time to cool down between between consecutive runs.</li>
+                            <li>Some devices might need time to cool down between consecutive runs.</li>
                         </ul>
                     </div>
                     <div class="buttons section-footer">