Merge branch 'master' into zh
Merge branch 'master' into zh
[zh_CN] fix build warning in /zh/models/deleting-data.rst
[zh_CN] done /zh/models/datasources.rst
still need to remove ro for PDF
Merge pull request #1958 from blackpuppy/zh

[zh_CN] done /zh/models/datasources.rst
[fr] follow #1951