add error responses to activity REST docs
add documentation for 200 responses
add error responses to authentication REST docs
add error responses to authentication REST docs
add error responses to config REST docs
document REST responses for content API
document REST responses for discussions module
update REST documentation for docs module
document REST responses for following module
document REST responses for mediacore module
document REST responses for preview processor
document REST responses for principals module
document REST responses for search module
document REST responses for telemetry module
document REST responses for tenants module
document REST responses for UI module
document REST responses for uservoice module
change 204 status codes to 200
REST Doc HttpResponses follow-up

* Removed parentheses
* Took some duplicate stuff out
* Expanded where necessary
Merge branch 'rest-errors'

* rest-errors:
  REST Doc HttpResponses follow-up
  change 204 status codes to 200
  document REST responses for uservoice module
  document REST responses for UI module
  document REST responses for tenants module
  document REST responses for telemetry module
  document REST responses for search module
  document REST responses for principals module
  document REST responses for preview processor
  document REST responses for mediacore module
  document REST responses for following module
  update REST documentation for docs module
  document REST responses for discussions module
  document REST responses for content API
  add error responses to config REST docs
  add error responses to authentication REST docs
  add error responses to authentication REST docs
  add documentation for 200 responses
  add error responses to activity REST docs