(docs): `SliderMark` not mentioned in the doc, and `SliderThumb` with tooltip

Hello,

The SliderMark tag is not mentioned in the online documentation. Here is an example.

That said, I find it’s easier to set a tooltip to the SliderThumb.

  const [sliderValue, setSliderValue] = React.useState(5);
  <Slider id="slider" defaultValue={5} min={0} max={10} colorScheme="blue" onChange=(v) => {setSliderValue(v)}>
    <SliderTrack>
      <SliderFilledTrack />
    </SliderTrack>
    <Tooltip hasArrow bg="red.600" placement="top" closeOnClick={false} isOpen label={sliderValue}>
      <SliderThumb />
    </Tooltip>
  </Slider>

[YenTingWu]

I’ll take this issue

[stla]

By the way there is also RangeSliderMark now. But well, it’s not necessary to provide an example once an example of SliderMark is given.

Cheers.