MAINT: Fix warnings generated by convert_datatype.h
MAINT: Fix warnings generated by convert_datatype.h

The convert_datatype.h file needs to be updated with sized arrays to
match the function definitions in convert_datatype.c.

rgommers/numpy,endolith/numpy,mhvk/numpy,anntzer/numpy,charris/numpy,mattip/numpy,pdebuyl/numpy,seberg/numpy,jakirkham/numpy,mhvk/numpy,pdebuyl/numpy,mattip/numpy,simongibbons/numpy,rgommers/numpy,anntzer/numpy,rgommers/numpy,pdebuyl/numpy,anntzer/numpy,charris/numpy,numpy/numpy,endolith/numpy,jakirkham/numpy,simongibbons/numpy,numpy/numpy,seberg/numpy,seberg/numpy,endolith/numpy,jakirkham/numpy,jakirkham/numpy,mhvk/numpy,charris/numpy,jakirkham/numpy,endolith/numpy,mattip/numpy,mhvk/numpy,numpy/numpy,simongibbons/numpy,mattip/numpy,anntzer/numpy,charris/numpy,rgommers/numpy,mhvk/numpy,seberg/numpy,simongibbons/numpy,simongibbons/numpy,pdebuyl/numpy,numpy/numpy