Add zh to the languages field in the build_documentation.yml and build_pr_documentation.yml files

Remove all these sections that haven't been translated yet
Remove Chapter 0 from the table of contents since it hasn't been translated yet

Fixed an error in the translation format of Chapter 1, Section 3

·Fixed some formatting errors
·Moved Chapters 0 and 2 to Simplified Chinese

Formatting revisions and some translation corrections

Co-authored-by: Suteera <[email protected]>

* typo & error mitigation

* consistency

* Trainer.predict() returns 3 fields

* ran make style

* added chapter 1/6 to _toctree.yml

* [TR] Translated Chapter 1.6 🤗

* Fixes to chapter 7

Co-authored-by: lewtun <[email protected]>

It should be "Обучающий цикл" not "Обучающий цикла"

…er1 (#351)