Fixes some chinese translation

* Changed a halfwidth exclamation mark (!) to a fullwidth one (！)
* Fixed some confusing translation
    * 序列简介 (sequential intro) → 基础篇 (basic intro)
    * 私藏一个提交 (add a commit to one's private collection) → 只取一个提交 (get only one commit)
* Fixed various typos etc...