Generate `// CLIF macro` comments.
Generate `// CLIF macro` comments.

Legacy PyCLIF generates `// CLIF macro` comments for `Interface`. We would like to make pybind11 code generator behaves the same: https://source.corp.google.com/piper///depot/google3/third_party/clif/python/pyext.py;l=794.

This is to make google3/quality/ranklab/future_oss/data_structures/python/vector_wrapper.clif work.

PiperOrigin-RevId: 436309008

google/clif,google/clif,google/clif