small cleanup of trigger event javadoc

 * Trigger Sensors are sensors that trigger an event and are automatically

 * disabled. {@link Sensor#TYPE_SIGNIFICANT_MOTION} is one such example.

 * <p>

 * SensorManager lets you access the device's {@link android.hardware.Sensor

 * sensors}. Get an instance of this class by calling

 * {@link SensorManager} lets you access the device's {@link android.hardware.Sensor

 * sensors}. Get an instance of {@link SensorManager} by calling

 * {@link android.content.Context#getSystemService(java.lang.String)

 * Context.getSystemService()} with the argument

 * {@link android.content.Context#SENSOR_SERVICE}.

 * Usage details are explained in the example below.

 * </p>

 * <p>Here's an example setup for a TriggerEventListener:

 *

 * <pre class="prettyprint">

 * <pre>

 * class TriggerListener extends TriggerEventListener {

 *     public void onTrigger(TriggerEvent event) {

 *          // Do Work.