Add outline to low-contrast star icons in ARIA icon font working example

Addresses one of the side concerns from #1016

Author: patrickhlauke

working-examples/aria-icon-font-img-role/index.html

@@ -44,8 +44,8 @@
     .icon-star-bg:before    { content: "\e982"; }
     .icon-star-half:before  { content: "\e983"; }
 
-    .grey { color: #949494; }
-    .yellow { color: #f8c102; }
+    .grey { color: #949494; -webkit-text-stroke: 1px black; }
+    .yellow { color: #f8c102; -webkit-text-stroke: 1px black; }
 
     /* EXAMPLE 2 */