[doc] Update installation instructions
[doc] Update installation instructions

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