Improve types for electronic_structure.{core/dos}

[DanielYang59]

Summary

• Improve types and docstring cleanups for (follow up of Improve types for electronic_structure.{bandstructure/cohp} #3873):
  • electronic_structure.core
  • electronic_structure.dos
• Nest private classmethod (which should not be classmethod but staticmethod) get_transformation_matrix inside get_moment method 2843854, rationale:
  • It's used by get_moment alone
  • No unit test added for get_transformation_matrix (usually I would expose such internal function as private method if I need to unit test it)

[DanielYang59]

@janosh Apologize for trying to mess up your weekend, just ping you to get this tracked as well and no rush at all. Thanks!

[janosh]

Good stuff! Thanks

[DanielYang59]

Thanks! Have a nice weekend ahead!