fix: check how ions are imported currently #186

Problem

The cif parser is now loading cif files with atom types specified as ions, e.g., Zr4+, without crashing. But we aren't sure whether it is just ignoring the 4+ or correcting the form factor for that case.

Proposed solution

Check the code. We would rather use a more comprehensive lookup table that has all the ions rather than turning them all to atoms by removing the "N+". Check if that is being done and do it if it isn't