[zh-hans] use zh-hans instead of zh-cn

[lanceli]

Currently the docs of simplified Chinese shown traditional Chinese by gitbook.
Use zh-hans instead of zh-cn to fix it.

Refs:

• GitbookIO/gitbook@5d1c4d2

https://github.com/GitbookIO/gitbook/blob/b48f8472d35b27d549d7c9a5b61f77f6b78e1908/CHANGES.md#260

[Jinjiang]

This will lead the existing zh-cn links broken. I suggest to keep the current links available first and think another way instead.
Thanks

[lanceli]

For me it's better to change all existing zh-cn links to zh-hans in the long term, and there is same issue with others docs, e.g. vue-loader

[Jinjiang]

I found that the default theme of GItbook don't have _i18n/zh-cn.json. So it automatically matches to _i18n/zh-tw.json.

My suggestion is create a PR to gitbook theme-default to add a zh-cn.json file. There are two main reasons: 1. Actually all current content translation is simplified Chinese (except the GitBook theme itself); 2. The zh-cn urls has been published.

Thanks.

[lanceli]

Up to you, and i do not think they will accept your suggestion base on this: GitbookIO/gitbook#926
and GitbookIO/gitbook@5d1c4d2