Add an option for format the Pit value in the RangeSlider

[samouss]

Do you want to request a feature or report a bug?

Feature.

Feature: What is your use case for such a feature?

With the current implementation of the Slider we can format the tooltip value but not the Pit value. In some cases the computed value has a decimal but it's not always relevant (e.g. year).

Feature: What is your proposed API entry? The new option to add? What is the behavior?

Add a similar option to RangeSliderTooltipOptions for the Pit value.

[bobylito]

Sounds reasonable given that we already have an option for the tooltip.