Document new rate limits on endpoints

Magdalena Frankiewiczrequested to merge
document_rate_limits_for_users_sign_up_username_update_and_username_exists_endpoints into master

What does this MR do and why?

This MR adds documentation for recently added rate limits on user sign_up, username update and username exists endpoints.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

Edited by Evan Read

Merge request reports