Remove the deprecated reciprocal lattice point class

[hakonanes]

Description of the change

Removes the deprecated diffsims.crystallography.ReciprocalLatticePoint class, which was deprecated in June 2022. Closes #189.

Three methods in the public API for generating sets of {hkl} were not deprecated. These have improved replacements in the "new" ReciprocalLatticeVector class:

• get_hkl() -> from_highest_hkl()
• get_highest_hkl() -> from_min_dspacing()
• get_equivalent_hkl() -> symmetrise()

These functions should be deprecated and the user "new" methods. This can be done with the deprecation tools from #199, which should be merged before this PR.

Progress of the PR

• Docstrings for all functions
• Unit tests with pytest for all lines
• Clean code style by running black
• Deprecate old methods to get sets of reciprocal lattice vectors

For reviewers

• The PR title is short, concise, and will make sense 1 year later.
• New functions are imported in corresponding __init__.py.
• New features, API changes, and deprecations are mentioned in the
  unreleased section in CHANGELOG.rst.
• Contributor(s) are listed correctly in credits in diffsims/release_info.py and
  in .zenodo.json.

[CSSFrancis]

@hakonanes Looks good. Some comments on adding extra infromation a couple of places while we are changing this code.

It might be worth adding information about the manifest and manifix to the developer guide if you think it is worth it but that can wait.

[CSSFrancis]

Add a comment something along the lines of:

# For more information on managing files in pacakge 

[hakonanes]

The links now have a description.

[CSSFrancis]

Suggested change

	"""Return the highest Miller indices hkl of the plane with a direct
	space interplanar spacing greater than but closest to a lower
	threshold.
	Parameters
	"""Return the highest Miller indices hkl of the plane with a direct
	space interplanar spacing(d-spacing) greater than but closest to the ``min_dspacing``.
	Parameters

[hakonanes]

Thanks, I've added "(d-spacing)" and referred to the variable name (in italics instead of code-style, as used by NumPy).

[hakonanes]

I thought I'd resolved merge conflicts locally, but alas. I believe the issue relates to a small change you made in the reciprocal_lattice_point.py file, @CSSFrancis (6a7ac0b), which I here delete. I'll make a new branch and PR.

[hakonanes]

I take that back, I don't really know what exactly caused the conflict (the addition of the deprecation decorators were e.g. taken as changes in this PR rather than coming from the main branch).