correct arange docs (#21992)
Summary:
https://github.com/pytorch/pytorch/issues/21579 correctly points out an inaccuracy in the docs for `arange`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21992
Differential Revision: D15914411
Pulled By: umanwizard
fbshipit-source-id: 3eb1734b29af3f3858f0f4d54c71e28dbda5c75b
