Use {{ref-framerate}} instead on {{main-framerate}} for distorted files

[fifonik]

FFMetrics scaling distorted to reference resolution.
It should probably do the same for framerate.

At this moment this can be done by creating FFMetrics.conf with the following content:

{
	"Metric": {
		"Template": "-hide_banner -nostdin -r {{ref-framerate}} -i {{main-src}} -r {{ref-framerate}} -i {{ref-src}} -frames:v {{duration}} -lavfi {{lavfi}} -f null -"
	}
}

Notice -r {{ref-framerate}} before -i {{main-src}}