Tidy up rs_sig_args() docstring.
Tidy up rs_sig_args() docstring.

librsync/librsync,sourcefrog/librsync,librsync/librsync,sourcefrog/librsync,dbaarda/librsync,sourcefrog/librsync,dbaarda/librsync,dbaarda/librsync,librsync/librsync,dbaarda/librsync,librsync/librsync,sourcefrog/librsync