[Feature] TreePathInfo property of sunburst chart label formatter params could be adopt by document and TS

[Mingeax]

What problem does this feature solve?

Aiming to display tree structure data, and show the ratio of every data item, sunburst charts should provide both of the information to its label formatter params.

But, up to now params still can't receive that, by document. However, actually there is a property 'treePathInfo', which contains the value of the data item and its ancestors. And its length represents the level of data items. Thus we can simply calculate the ratio and get the hierarchy. Unfortunately, both document and TS don't acknowledge it.

I don't know what authority's attitude towards this property is, but I hope it can be formal in the future.

What does the proposed API look like?