Sankey hoverinfo options not honored

As of right now, Sankey traces ignore all hoverinfo options except for ‘none’ and ‘skip’.

https://codepen.io/anon/pen/xyrXXm

[antoinerg]

I wrote my last comment a bit too fast. We already have node and link attributes so I should just use them 🤔

[alexcjohnson]

That makes sense. I guess we could also have the upcoming templates on hover be split into node.hovertemplate and link.hovertemplate 🤔

Yes, I think those had better be separate too.

@antoinerg and I had a discussion about how to handle this for other types that support hoveron or otherwise have multiple classes of hoverable items - like scatter, how would we specify separate point and fill (and eventually line) hover templates (or separate hoverinfo and hoverlabel style)? Tentative conclusion was that trace.hover(info|template|label) should apply only to points, we should make a new container trace.fills.hover(info|template|label) for fill hover (and perhaps at least hoverlabel would be inherited from trace.hoverlabel) and when we get around to line hover we can add those to the existing line container, ie trace.line.hover(info|template|label). Any other ideas?