Fix map/coerce rule for newtypes with wrappers
This addresses Trac #16208 by marking newtype wrapper unfoldings as compulsory.
Furthermore, we can remove the special case for newtypes in exprIsConApp_maybe (introduced in 7833cf40).
This addresses Trac #16208 by marking newtype wrapper unfoldings as compulsory.
Furthermore, we can remove the special case for newtypes in exprIsConApp_maybe (introduced in 7833cf40).