code: public Element svgLine(double x1, double y1, double x2, double y2) {
      return SVGUtil.svgLine(document, x1, y1, x2, y2);
    }
docs: Create a SVG line element
  
  @param x1 first point x
  @param y1 first point y
  @param x2 second point x
  @param y2 second point y
  @return new element