By the way, in case you're wondering... the %copy signature is this here:
(f x)
Yeah, that tiny little thing. What that does is it takes the %copy method and calls it with the object as its first argument. That's it. As long as that doesn't change, then there's no need to update the objects.
So, if we wanted to add in some new copy functionality that required us to pass more information to the %copy method, we'd need to change the copy function to pass more arguments to the %copy method, which would require changes to all the objects that use the %copy method.
But in this case, we don't need to pass any more arguments to the %copy method so nothing changes except the copy function itself.
And the copy function uses @r which means "0 or more extra arguments", so it works just fine in the 1-argument case. Thus, this change is backwards compatible in every way (that I care about).
