capitalize HTML5 in Getting Started Guide

these pages capitalize “HTML5”:

http://en.wikipedia.org/wiki/HTML5
http://dev.w3.org/html5/spec/
http://www.html5rocks.com/en/

guides/source/getting_started.textile

@@ -1129,7 +1129,7 @@ together.
 Here we're using +link_to+ in a different way. We wrap the
 +:action+ and +:id+ attributes in a hash so that we can pass those two keys in
 first as one argument, and then the final two keys as another argument. The +:method+ and +:confirm+
-options are used as html5 attributes so that when the link is clicked,
+options are used as HTML5 attributes so that when the link is clicked,
 Rails will first show a confirm dialog to the user, and then submit the
 link with method +delete+. This is done via the JavaScript file +jquery_ujs+
 which is automatically included into your application's layout