docs: fixed type in rev number (24 changed to 23)

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  <p id="rev24-1-0"><a href="#" onclick="return toggleContent(this)">

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    <img src="{@docRoot}assets/images/triangle-opened.png" class="toggle-content-img" alt=""

/>Android Support Library, revision 24.1.0</a> <em>(October 2015)</em>

/>Android Support Library, revision 23.1.0</a> <em>(October 2015)</em>

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