The Chef docs are created from an archive that resides here https://docs-archive.chef.io/. These docs are not updated any more, which I was told on Slack by a Chef employee (sorry for not having anything written down).
The chef docs moved to a style of documentation that is independent of the chef version, so scraping the cookbooks reference from the official docs page (https://docs.chef.io/cookbooks.html) would probably the best approach.