Fixed typo. "a a" -> "a"

    <dt><code>ScriptC_helloworld</code></dt>

    <dd>This class is generated by the Android build tools and is the reflected version of the

    <code>helloworld.rs</code> Renderscript. It provides a a high level entry point into the

    <code>helloworld.rs</code> Renderscript. It provides a high level entry point into the

    <code>helloworld.rs</code> native code by defining the corresponding methods that you can call

    from the traditional framework APIs.</dd>