No startPoint prop in Slider component

[kitcat-dev]

Hello! I recently asked about the lack of the property startPoint in Gravity UI Slider's API in the Telegram channel. Even though it is supported in react-component/slider.

We need this because if we are dealing with a range, for example, from -2 to +2, the current value is -1 and the default value is 0, then the range from -1 to 0 should be highlighted, not from -2 to -1.

I saw the announcement about changes in Gravity UI v7, but I want to also create this issue so ensure this request is not lost and this prop will be supported in the current or next major version. I can make that contribution myself, if there is no capacity for that change yet.