update icon to code (#6)

Author: jsirish

icons/code-icon.svg

@@ -15,7 +15,7 @@ class ElementEmbeddedCode extends BaseElement
     /**
      * @var string
      */
-    private static $icon = 'code-icon';
+    private static $icon = 'font-icon-code';
 
     /**
      * @var string