fix(stateTimeline): add missing insertNulls and spanNulls options to fieldConfig.defaults.custom

[aamkye]

Where should I edit files to achieve the following result?
I'm also interested in contributing to the docs :)

[CLAassistant]

All committers have signed the CLA.

[Duologic]

As you found out, that code is generated. When schemas upstream in grafana/grafana get updated with these fields, then this'll also appear in Grafonnet.

See similar issue: #188

As suggested there, a workaround can be done byy adding a JSON blurb to your panel:

panel + {
  fieldConfig+: {
    defaults+: {
      custom+: {
        insertNulls: '<value>',
      },
    },
  },
}