[doc] Add missing C functions
[doc] Add missing C functions

chemfiles/chemfiles,lscalfi/chemfiles,chemfiles/chemfiles,lscalfi/chemfiles,lscalfi/chemfiles,chemfiles/chemfiles,lscalfi/chemfiles,Luthaf/Chemharp,Luthaf/Chemharp,Luthaf/Chemharp,chemfiles/chemfiles