Update documentation with credit to Alex Walch

gui/index.html

@@ -897,6 +897,7 @@ span.mainfunction {color: #993300; font-weight: bolder}
 	<h3>Summary</h3>
 	<div class=tooltipinfo>
 	<p>Receive S/PDIF digital audio and resample to Teensy's audio sample rate.</p>
+	<p>Asychronous resampling contributed by <a href="https://github.com/alex6679">Alex Walch</a>.</p>
 	</div>
 	<h3>Boards Supported</h3>
 	<ul>