feat(CategoryTheory/Comma/Basic): use to_dual more (leanprover-community#40355)

This PR continues tagging things about `Comma` with `to_dual`.

This PR also expands the `to_dual_name_hint` syntax so that you can give multiple name hints with a single command, instead of having to repeat the command.

This PR adds `CategoryTheory.Comma.map_obj_hom'`, the dual of `CategoryTheory.Comma.map_obj_hom`.

Author: JovanGerb