Progress bar documentation (#240)
* Progress bar documentation
* Fill in accessibility docs a bit more
* Formatting
* More formatting
* Formatting
* Remove extra size
* Review comments
* Layout improvements
* Respond to feedback
* More review updates
* move Indeterminate section
* Remove unneeded sentence
* more examples
* consistency
* more fixes
Co-authored-by: Danni <darobins@adobe.com>
