* [Doc] Add CN chapter 5
* [Doc] Add CN 5.1
* [Doc] Add CN 5.2, 5.3, and 5.4 raw text
* [Doc] Add CN 5.2, 5.3, and 5.4 raw text
* [Doc] Put 5.1 CN parts
* [Doc] Put 5.2,5.3, and 5.4 raw CN parts
* [Doc] Fix linkage bugs.
* [Doc] 1st round of copyediting, Chapter5, 5.1, and part of 5.2
* [Doc] 2nd round of copyediting, removing EN parts.
* [Doc] 2nd round of copyediting, removing EN parts.
* [Doc] 2nd round of copyediting, removing EN parts.
* [Doc] 2nd round of copyediting, removing EN parts.
* [Doc] 3rd round of copyediting.
* [Doc] 4th round of copyediting to Minjie's comments.
* [Doc] 4th round of copyediting to Minjie's comments.
* [Doc] 4th round of copyediting to Minjie's comments.
* [Doc] 4th round of copyediting to Minjie's comments.
* [Doc] 4th round of copyediting to Minjie's comments.
* [Doc] 4th round of copyediting to Minjie's comments.
* [Doc] 5th round of copyediting to Murphy's comments.
* [bug][doc] Fix bug in batched heterograph training documentation
* added references of "above" with hyperlinks
* address comments
* fix API doc on EdgeDataLoader
Co-authored-by: Mufei Li <mufeili1996@gmail.com>