Synopsis (syntax) now shown before description in help page
Synopsis (syntax) now shown before description in help page

More in line with traditional man page format, and should allow longer
descriptions without hiding the brief synopsis line.

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