Improve doc of use_cache (#5912)
Improve doc of use_cache (#5912)

* Improve doc of use_cache

* Update src/transformers/configuration_xlnet.py

Co-authored-by: Teven <b89726cd754aacedfbfbdadf726478056c4b96d9@gmail.com>

Co-authored-by: Teven <b89726cd754aacedfbfbdadf726478056c4b96d9@gmail.com>
huggingface/transformers,huggingface/transformers,huggingface/transformers,huggingface/transformers,huggingface/pytorch-transformers