function updateTitle(dataPoint) {
            const textTitle = getTooltipTitle(dataPoint[dateLabel]);

            tooltipTitle
                .text(textTitle)
                .call(textWrap, tooltipMaxTitleLength, getTooltipTitleXPosition());
        }
Updates value of tooltipTitle with the data meaning and the date
@param  {Object} dataPoint Point of data to use as source
@return void
@private