Keep generated content in sync with static content in README automatically

Rolling out strings will eventually require us to remove the long reference sections from module READMEs. This will be a big change for a lot of users, so we'll want to make sure that strings docs are 100% ready to go before we start removing reference sections.

As such, it will be necessary to have an interim step where we have docs both in the README and as comments in the source code. In order to manage this reasonably, we'll want to have the comments be the source of truth and run strings against them to update the README reference section accordingly. The goal of this ticket is to add a feature that will let us do that.