code: def to_rst(cls) -> str:
          
          sep_line = '+' + 6 * '-' + '+' + '-' * 71 + '+\n'
          blank_line = '|' + 78 * ' ' + '|\n'
          table = ''
          for group in cls.groups:
              table += sep_line
              table += blank_line
              table += '|' + '**{}**'.format(group.name).center(78) + '|\n'
              table += blank_line
              for error in group.errors:
                  table += sep_line
                  table += ('|' + error.code.center(6) + '| ' +
                            error.short_desc.ljust(70) + '|\n')
          table += sep_line
          return table
docs: Output the registry as reStructuredText, for documentation.