Direct-C generates wrong binding names for abstract class type-bound procedures.

Reproduction:

cd f90wrap/examples/issue41_abstract_classes
make -f Makefile.meson DIRECTC=yes clean test

Error: AttributeError: module 'itest' has no attribute 'f90wrap_myclass_base__get_value__binding__myclass_t'. Did you mean: 'f90wrap_myclass_impl__get_value__binding__myclass_impl_t'?

Affected: issue41_abstract_classes