doc: Adds new Ref var usage to readme

Author: NeedleInAJayStack

src/README.md

@@ -68,10 +68,10 @@ To use them, simply enter the value in the input string. Below is an example of
 You can use the Haystack connector to source new variables. Create a query and then enter the name of the column that
 contains the variable values. If no column is specified, the first one is used.
 
-The value injected by the variable exactly matches the displayed value, with the exception of Ref types, where the
-injected value is only the ID portion (i.e. the dis name is not included in the interpolation). Multiple-select values
-are combined with commas, (`red,blue`), but this may be customized using the
-[advanced variable format options](https://grafana.com/docs/grafana/latest/dashboards/variables/variable-syntax/#advanced-variable-format-options).
+The value injected by the variable exactly matches the displayed value, with the exception of Ref types. Instead, Ref
+types display the "display" portion and inject only the "ID" portion (i.e. `@abc "Site A"` will be displayed as `Site A`
+and provide `@abc` when injected). Multiple-select values are combined with commas, (`red,blue`), but this may be
+customized using the [advanced variable format options](https://grafana.com/docs/grafana/latest/dashboards/variables/variable-syntax/#advanced-variable-format-options).
 
 ### Alerting