[zh_CN] done /zh/models/saving-your-data.rst
[zh_CN] follow en changes
[fr] corrections
Merge pull request #1926 from blackpuppy/zh

[zh_CN] done /zh/models/saving-your-data.rst
Remove third level nav elements.

Having extra nav elements is kind of nice but kind of a pain in the ass
as well. It creates painful maintenance busy work that is totally not
necessary as both the book and the api have version pickers.
Remove CSS for third level nav.