Normalise to / in generating interface names
Normalise to / in generating interface names

In practice, this is only for consistency in the tests. Is this the
right way?

mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm