For AS5, the documentation process is a bit ad hoc. Most jira issues do not result in a needed change for the core documentation. For those issues that do require a doc change, what I can tell you now is that the core doc might get updated, and it might not. It's more likely that the change will be reflected in the release notes and on a wiki page somewhere.
For AS6, we are hoping to improve this as we make it easier for AS developers to update the documentation directly. The goal is that the documentation would be versioned along with each release if not sooner.