Photonuclear ACE file processing does not handle MF5 LF=5, 11 or 12

[whaeck]

Photonuclear data processing in ACER only processes MF5 data with LF=1 (arbitrary tabulated function), LF=7 (simple Maxwellian fission spectrum) and LF=9 (evaporation spectrum). Other options for LF lead to an error message.

As far as I can tell, only Am241 in the ENDF/B-VIII.0 photonuclear data sublibrary has this issue but it went undetected because this evaluation has MF4 MT18 missing (which makes NJOY skip neutrons from fission in the resulting ACE file - this is the subject of a separate issue). A fixed version of the Am241 evaluation (attached to this issue) causes the error to pop up.

input-am241.njoy.txt
am241-pn-endf7-corrected.endf.txt