Unclear documentation / naming in turtle.env.model.Registry

[gavin-norman-sociomantic]

The module doc says:

Provides centralized registry where turtle env additions from other libraries can register themselves for the purpose of being notified about test suite shutdown.

The one location where the Registry.unregisterAll method is called says:

before killing tested app, unregister all know environment additions to avoid irrelevant errors being printed because of shutdown sequence

The documentation of ITurtleEnv says:

Turtle environment addition must implement this interface to be able to be notified about test suite shutdown to adjust own state accordingly.

The documented purposes of the registry and the unregistration facility (bolded above) don't really seem to tie in. From the point of view of a user implementing ITurtleEnv, it's not clear what unregister is supposed to do.

[gavin-norman-sociomantic]

(Guessing this is a result of refactoring.)