Hovers on cumulative histograms

[nicolaskruchten]

In this pen: https://codepen.io/nicolaskruchten/pen/RJLMVb?editors=0010# I see that the hovers label the first bin as "1" with a value of 2 and the second as "3" with a value of 3. It seems to me that the hover labels should indicate the upper edge of the bin, not its center: there are 2 values below 2, not below 1.

[etpinard]

I can't remember what @alexcjohnson had in mind for cumulative histogram hover back in #2113, but yeah this seems off.

Thanks @nicolaskruchten for the report.

[etpinard]

Just found #2115 - which describes some potential cumulative histogram hover content.

Merging into #2115