Fix type in CSS class name

homeassistant/components/frontend/www_static/polymer/resources/home-assistant-style.html

@@ -13,7 +13,7 @@
 .divider-color         { border-color: #B6B6B6; }
 
 /* extra */
-.accent-text-colo      { color: #FF9800; }
+.accent-text-color      { color: #FF9800; }
 
 body {
   color: #212121;