code: func massageDotSVG() PostProcessor {
  	generateSVG := invokeDot("svg")
  	return func(input io.Reader, output io.Writer, ui plugin.UI) error {
  		baseSVG := new(bytes.Buffer)
  		if err := generateSVG(input, baseSVG, ui); err != nil {
  			return err
  		}
  		_, err := output.Write([]byte(massageSVG(baseSVG.String())))
  		return err
  	}
  }
docs: // massageDotSVG invokes the dot tool to generate an SVG image and alters
  // the image to have panning capabilities when viewed in a browser.