Fix a typo.

 *     <li><code>Result</code>, the type of the result of the background

 *     computation.</li>

 * </ol>

 * <p>Not all types are always used by am asynchronous task. To mark a type as unused,

 * <p>Not all types are always used by an asynchronous task. To mark a type as unused,

 * simply use the type {@link Void}:</p>

 * <pre>

 * private class MyTask extends AsyncTask<Void, Void, Void> { ... }