Just import torch AdamW instead (#36177)

* Just import torch AdamW instead

* Update docs too

* Make AdamW undocumented

* make fixup

* Add a basic wrapper class

* Add it back to the docs

* Just remove AdamW entirely

* Remove some AdamW references

* Drop AdamW from the public init

* make fix-copies

* Cleanup some references

* make fixup

* Delete lots of transformers.AdamW references

* Remove extra references to adamw_hf

docs/source/zh/main_classes/optimizer_schedules.md

@@ -22,10 +22,6 @@ rendered properly in your Markdown viewer.
 - 继承自 `_LRSchedule` 多个调度器：
 - 一个梯度累积类，用于累积多个批次的梯度
 
-## AdamW (PyTorch)
-
-[[autodoc]] AdamW
-
 ## AdaFactor (PyTorch)
 
 [[autodoc]] Adafactor