Word wrap List Headings with JSON

[StanBaer]

I cannot find a way to successfully force the column headings in a list to wrap instead of truncate... using JSON.  The only post I found is below, and that didn't work.

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/column-formatting.schema.json",
  "elmType": "div",
  "style":{
        "white-space":"wrap"
  },
  "txtContent": "@currentField"
}