Plotrb camelcases some data fields for no apparent reason

[translunar]

I have the field :common_name in one of my data sets, and it gets turned into this:

    {
      "name": "minerals",
      "values": [
        {
          "commonName": "almandine",
          "low": 371,
          "high": 395

But elsewhere, references to common_name remain, so it won't plot properly:

    {
      "name": "absorbances",
      "type": "ordinal",
      "domain": {
        "data": "minerals",
        "field": "data.common_name"
      },
      "range": "height"
    },