change Site Language to Simplified Chinese failed.

[xd-git]

When I want to change the site language to Simplified Chinese according to the document(Click Here!), it tells me I should set the language attribute to zh-Hans in the site configuration file but I failed. Then I cd in the theme/next/languages/ and find zh-CN.yml file in it. So I think should I set the language to zh-CN, and finally it works! Please update the document. I'm appreciate your work about hexo-theme-next. Hope it getting better!