docs: make AD logo clickable on home page

                            </div><!-- end homeTitle -->

                            <div id="announcement-block">

                            <!-- total max width is 520px -->

                                <a href="{@docRoot}design/index.html">

                                  <img src="{@docRoot}images/home/android-design.png"

alt="Android Design" width="160px" style="padding:10px 33px 5px"/>

                                </a>

                                  <div id="announcement" style="width:275px">

    <p>Introducing <b>Android Design</b>: The place to learn about principles, building blocks, and patterns

      for creating world-class Android user interfaces. Whether you're a UI professional or a developer