* fix some docs bugs; test=document_fix

* Update batch_sampler.py

* Update dataset.py

* Update dataset.py

* Update sampler.py

* for codestyle; test=document_fix

* fix copy-from issue; test=document_fix
Co-authored-by: NLigoml <39876205+Ligoml@users.noreply.github.com>
Co-authored-by: Ligoml <limengliu@tiaozhan.com>