GitLab

* update booster_api.md

* update booster_checkpoint.md

* update booster_plugins.md

* move transformers importing inside function

* fix Dict typing

* fix autodoc bug

* small fix

* sharded optimizer checkpoint for gemini plugin

* modify test to reduce testing time

* update doc

* fix bug when keep_gatherd is true under GeminiPlugin

* [doc] add checkpoint related docstr for booster

* [doc] add en checkpoint doc

* [doc] add zh checkpoint doc

* [doc] add booster checkpoint doc in sidebar

* [doc] add cuation about ckpt for plugins

* [doc] add doctest placeholder

* [doc] add doctest placeholder

* [doc] add doctest placeholder