improve documentation of training_args.py (#8270)
* improve documentation of training_args.py
- do_train
- do_eval
- do_predict
* fix line too long
* fix style with black on training_args.py
* Update src/transformers/training_args.py
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
* Update src/transformers/training_args.py
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
* Update src/transformers/training_args.py
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
* fix line length with utils/style_doc
* black reformatting
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
