Returns a ChartLine object representing the high-low lines of a line or scatter series.
High-low lines connect the highest value in a group of series with the lowest. By default, high-low lines are colored black, have a Narrow weight
and a Solid style
. Note that scatter and area charts do not support high-low lines, so while you can set the high-low line properties, they will not appear in the output of a scatter or area series.