Change underlying of HKApply
Change underlying of HKApply

It's now the same as upperBound, i.e. the underlying of the
type constructor re-applied to the arguments.

som-snytt/dotty,dotty-staging/dotty,lampepfl/dotty,som-snytt/dotty,dotty-staging/dotty,dotty-staging/dotty,lampepfl/dotty,sjrd/dotty,sjrd/dotty,som-snytt/dotty,som-snytt/dotty,lampepfl/dotty,lampepfl/dotty,sjrd/dotty,dotty-staging/dotty,sjrd/dotty,lampepfl/dotty,dotty-staging/dotty,sjrd/dotty,som-snytt/dotty