[sync]
support ES6 fat arrow
https://github.com/einars/js-beautify/commit/941bbd0859b15ecd6dab4a1951a2977f45ae8b67
Add support for ES6 template strings
https://github.com/einars/js-beautify/commit/507977eff317c34c59bb632f00e2df2849a35a8a