Robert Pitt

`provider`: add documentation regarding session logout.

6

### Community Guidelines - [x] I have read and agree to the [HashiCorp Community Guidelines ](https://www.hashicorp.com/community-guidelines). - [x] Vote on this issue by adding a 👍 [reaction](https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/) to the original...