Fix up naming in derived type example

The problem

We want to support wrapping derived types that have allocatable attributes. The counter-example to this is derived types that have attributes which are pointers. Right now, our derived type example is named in a way that doesn't make clear what it is testing. For example, the derived type which has another derived type as an attribute is called parent, even though there is no sub-classing, which is misleading.

Definition of "done"

• Rename DerivedTypeParent to DerivedTypeViaPointer
• Other renaming consistent with the change above

Additional context

Started on this here, but will split out to make life simpler