DRAFT: rpc:release: document new intended behavior
We've decided that we want to move rpc:release to be a "universal" method implemented as a special case, and applying to all object IDs.
This commit contains the documentation and API for the new method. (This necessarily breaks compilation; don't merge this as-is.) @Diziet, If you're fine with the new API and documentation, I'll close this MR and open a new MR to make the changes.