connectomestats: Alter output file names
connectomestats: Alter output file names

Remove underscore between output prefix and fixed output file suffixes, in order to make output file names more consistent with other MRtrix3 statistical inference commands.

MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3