update node 5 'unexpected token'

lib/vendor/markdown-it.js

@@ -34,7 +34,7 @@ var $markdown = require('markdown-it')({
     .use(require("markdown-it-component"))
     .use(require("markdown-it-task-lists"))
     .use(require("markdown-it-fontawesome"))
-    .use(require('markdown-it-highlightjs'))
+    //.use(require('markdown-it-highlightjs'))
     //.use(require("markdown-it-prism"))
 ;