/**
* Configuration properties for tooltip.
*
* @public
* @module TooltipFormatter
*
* @param {DataModel} dataModel data model instance containing all rows which needs to be shown in the tooltip.
* @param {Object} context Additional information for formatting tooltip.
* @param {Object} context.axes Instances of axis.
* @param {ColorAxis} context.axes.color Color axis instance.
* @param {SizeAxis} context.axes.size Size axis instance.
* @param {ShapeAxis} context.axes.shape Shape Axis instance.
*
* @return {Array|Function} Array of arrays containing values to displayed in a row or function returned by
* ```html``` operator available in {@link Operators}.
* ```
* This method can return output in this format,
* [
* ['Origin', 'USA'],
* ['Cylinders', {
* value: '6',
* style: {
* 'font-weight': 'bold'
* }
* }]
* ]
* Every sub array in the array represents a row in the tooltip content and each value can be as string or object.
* Or it can be in this format,
* html`<div>Origin</div><div>USA</div>`
* ```
*/