Use of `List` vs `Array` vs `Matrix`

[rowlesmr]

Prompted by discussions https://github.com/COMCIFS/cif_core/pull/399#issuecomment-1587415980 https://github.com/COMCIFS/cif_core/issues/269#issuecomment-1589186767, I had a look at the data items with non-Single container types.

They are:

List

• none

Array

• _pd_calc_overall.component_presentation_order
• _pd_calc.component_intensity_net_list
• _pd_calc.component_intensity_total_list

Matrix

• _pd_background.air_or_thermal_diffuse_coefs_1
• _pd_background.air_or_thermal_diffuse_coefs_1_su
• _pd_background.air_or_thermal_diffuse_coefs_2
• _pd_background.air_or_thermal_diffuse_coefs_2_su
• _pd_background.chebyshev_coefs
• _pd_background.chebyshev_coefs_su
• _pd_background.cosine_fourier_series_coefs
• _pd_background.cosine_fourier_series_coefs_su
• _pd_background.line_segment_intensities
• _pd_background.line_segment_intensities_su
• _pd_background.line_segment_xs
• _pd_background.polynomial_coefs
• _pd_background.polynomial_coefs_su
• _pd_background.polynomial_powers
• _pd_background.polynomial_powers_su
• _pd_pref_orient_march_dollase.hkl
• _pd_pref_orient_spherical_harmonics.y_ij

I think all of these should be List, as they're just grouping together related values; they're not doing any maths with anything.

_pd_pref_orient_march_dollase.hkl could stay as a Matrix, as _refln.hkl is, too.

Will also need to rename _pd_calc.component_intensity_*_list to remove list from the name; maybe _pd_calc.component_intensities_*.