Add other measure values to custom tooltip on table calculation value using chart config override

[mr-sjhb]

Hello.

I want to add additional detail to a tooltip in Looker. The chart shows the value for a series which is from a table calculation, and I want the tooltip to show the value for the table calculation as well as one of the measures used in the table calculation. When working with measures I have done this using the html parameter with templating referencing other measures in the view. Since this is a table calculation I was hoping to find a way to do this through the chart config editor. As far as I understand from the documentation found here (https://cloud.google.com/looker/docs/chart-config-editor) and the Highchart API documentation, I am only able to use templates to reference data in the chart configuration (or values in the chart through {y}). Is there a way that I can reference other measures in the same explore from the chart config override? I hope this question is sufficiently clear. Thanks!