added -moz-osx-font-smoothing to the stylesheet which improves font rendering in firefox

services/web/public/stylesheets/core/type.less

@@ -5,6 +5,7 @@
 * {
   -webkit-font-smoothing: antialiased;
   text-rendering: optimizeLegibility;
+  -moz-osx-font-smoothing: grayscale;
 }
 
 // Headings