Merge pull request #21604 from mantidproject/20990_crystalfield_bugfixes

...ng/inc/MantidCurveFitting/Functions/CrystalFieldControl.h

...g/inc/MantidCurveFitting/Functions/CrystalFieldFunction.h

Framework/CurveFitting/src/Functions/CrystalFieldControl.cpp

...ework/CurveFitting/src/Functions/CrystalFieldFunction.cpp

.../CurveFitting/src/Functions/CrystalFieldMultiSpectrum.cpp

...CurveFitting/src/Functions/CrystalFieldSusceptibility.cpp

...work/PythonInterface/mantid/api/src/Exports/IFunction.cpp

Testing/Data/SystemTest/Sm2O3.cif.md5

...SystemTests/tests/analysis/CrystalFieldPythonInterface.py

docs/source/fitfunctions/CrystalFieldSusceptibility.rst

docs/source/interfaces/Crystal Field Python Interface.rst

docs/source/release/v3.12.0/direct_inelastic.rst

docs/source/release/v3.12.0/spectroscopy.rst

scripts/Inelastic/CrystalField/CrystalFieldMultiSite.py

scripts/Inelastic/CrystalField/__init__.py

scripts/Inelastic/CrystalField/fitting.py

scripts/Inelastic/CrystalField/function.py

scripts/Inelastic/CrystalField/normalisation.py

scripts/test/CrystalFieldMultiSiteTest.py

scripts/test/CrystalFieldTest.py