Supply doc is wrong about done

[Altreus]

The problem

Supply.tap is documented thus:

The &done callback is called when the done method on the supply is called

Whereas, there is no done method on Supply. It correctly documents a live supply:

For a live supply the done routine will be called on the parent Supplier

It is unclear whether an on-demand supply also has a parent Supplier with a done method.

It is also unclear how to stop an on-demand supply.