code: public function renderReadableSpec($renderHint = true)
      {
          $c1 = '';
          if ($this->short && $this->long) {
              $c1 = sprintf('-%s, --%s', $this->short, $this->long);
          } else if ($this->short) {
              $c1 = sprintf('-%s', $this->short);
          } else if ($this->long) {
              $c1 = sprintf('--%s', $this->long);
          }
          if ($renderHint) {
              return $c1.$this->renderValueHint();
          }
  
          return $c1;
      }
docs: get readable spec for printing.
  
  @param string $renderHint render also value hint