Check if the child theme is HTML5 or XHTML with Genesis

plugin.php

<?php
// Paste the code BELOW this line into your plugin.

/**
 * Check if the child theme is HTML5 or XHTML with Genesis
 *
 * @author Reasons to Use Genesis
 * @link http://reasonstousegenesis.com/genesis-html5/
 */
add_filter( 'genesis_footer_creds_text', 'rtug_currently_reading' );
function rtug_currently_reading() {
	
	if ( genesis_html5() )
		return 'I am currently reading <span itemscope itemtype="http://schema.org/Book"><em itemprop="name">Go Set a Watchman</em> by <span itemprop="author">Harper Lee</span></span>.';
	else
		return 'I am currently reading <em>Go Set a Watchman</em> by Harper Lee.';
	
}