Implement hovertemplate for candlestick and ohlc traces

[emilykl]

Closes #3437

This PR adds a hovertemplate attribute for ohlc and candlestick, allowing users to define a custom hover template for those traces.

hovertemplate: 'opened at %{open}<br>closed at %{close}<extra></extra>',

Notes

• The first commit of this PR runs the biome formatter which introduces some noise into the diff. Use this link to see only the meaningful changes.

• This PR also adds the hovertemplatefallback attribute for the two traces in question

• hovertemplate is ignored when hoverlabel.split is set to true. (Open to suggestions here but I couldn't see an obvious way to make split: true work with the hovertemplate API.)

• Two Jasmine tests added

This completes the list in #3437.

Thanks to @chriddyp for putting this on my radar!

To test

• Create a plot like this one:

Plotly.newPlot(
    "plot", 
    [
        {
            x: [1, 2, 3, 4, 5],
            low: [21, 13, 18, 16, 22],
            high: [34, 23, 25, 26, 24],
            open: [24, 16, 22, 23, 22],
            close: [22, 18, 21, 21, 23],
            type: 'candlestick',  // or 'ohlc'
            hovertemplate: 'opened at %{open}<br>closed at %{close}<extra></extra>',
            // hoverlabel: {split: true},  
            // if the above line is uncommented, `hovertemplate` should be ignored
            // and separate hover tooltips should be shown for open, high, low, and close
        }
    ], 
);

• Hover over the data and confirm that the hovertemplate is respected
• Confirm that if hoverlabel.split is set to true, the hovertemplate is ignored and the previous behavior is unchanged

[camdecoster]

As we discussed, there's an issue with implementing the split: true logic that makes the split hover info not show up. Could you look into that?

[emilykl]

@camdecoster The bug you found with split: true should be fixed now. Ready for another look. I also added a Jasmine test which tests split: true and hovertemplate together.

[camdecoster]

Looks good. Could you please add a draftlog before merging?