* [WIP][Doc] Add Data Structures and Elements

* fix

* add

* fix

* add chinses doc

* refactor

* fix

* fix typo

* fix

* fix

* fix typo

* Update docs/en/advanced_guides/structures.md

* Update docs/en/advanced_guides/structures.md

Co-authored-by: Miao Zheng <76149310+MeowZheng@users.noreply.github.com>

* [Doc] MMSeg 1.x Documentation

* revise index