docs: support library 22.1 feature updates

      information on using the Action Bar, see the

      <a href="{@docRoot}guide/topics/ui/actionbar.html">Action Bar</a> developer guide.

  </li>

  <li>{@link android.support.v7.app.ActionBarActivity} - Adds an application activity class that

      must be used as a base class for activities that uses the Support Library action bar

  <li>{@link android.support.v7.app.AppCompatActivity} - Adds an application activity class that can

       be used as a base class for activities that use the Support Library action bar

       implementation.

  </li>

  <li>{@link android.support.v7.app.AppCompatDialog} - Adds a dialog class that can be used as a base

      class for AppCompat themed dialogs.

  </li>

  <li>{@link android.support.v7.widget.ShareActionProvider} - Adds support for a standardized

    sharing action (such as email or posting to social applications) that can be included in an

    action bar.