Change the height of whiskers in barchart

[johannes-wolf]

Discussed in #97

^{Originally posted by John-Toohey January 4, 2025}
These whiskers on this barchart are too tall and thus overlap! How should I slim them down?

    #cetz.canvas({
      let data1 = (
        ([With Instruction], 11.15, 6.15),
        ([Without Instruction], 3.80, 5.20),
      )
      chart.barchart(
        size: (10, 2),
        label-key: 0,
        value-key: 1,
        error-key: 2,
        x-label: [Mean Instances of Sexist Language Identified],
        bar-style: (cetz.palette.new(colors: (luma(50%),))),
        data1,
        min: 0,
      )
    })

```</div>