Update diffsims dependency and getting hkl data from ReciprocalLatticePoint

[hakonanes]

Signed-off-by: Håkon Wiik Ånes hwaanes@gmail.com

Description of the change

• Set hard diffsims >= 0.4 dependency
• Update use of hkl data from diffsims.crystallography.ReciprocalLatticePoint from ._hkldata to hkl.data

Progress of the PR

• Docstrings for all functions
• Unit tests with pytest for all lines
• Clean code style by running black via pre-commit

For reviewers

• Check that the PR title is short, concise, and will make sense 1 year
  later.
• Check that new functions are imported in corresponding __init__.py.
• Check that new features, API changes, and deprecations are mentioned in
  the unreleased section in doc/changelog.rst.

[hakonanes]

Will merge when checks pass.