Corrected spelling.

Corrected spelling.
Merge pull request #178 from stanzhai/develop

【校对】解决一些冲突，修复一处代码错误
Merge pull request #179 from twlkyao/patch-1

Corrected spelling.
make gitbook
Merge pull request #181 from stanzhai/develop

【校对】完成首轮人工校对
make gitbook
fix 2.4 collection types