Support `Self` type with extension methods

Is There any way that we could write extension methods for generic types? For example:

    public static <T> T println(@This T thiz) {
        System.out.println(thiz); 
        return thiz;
    }

Or

    public static <T extends Collection<? extends Long>> T printMax(@This T thiz) {
        System.out.println(thiz.max(Long::compareTo));
        return thiz;
    }

Thanks again for this awesome library.

[rsmckinney]

Fixed with af9746b

Watch the Self Type documentation for details

[rsmckinney]

UPDATAE:

With release 0.47-alpha @Self has been rewritten to fully support the Self type. Use it in method return types, parameter types, and field types. Learn more.