Feature request/idea: Show sum in env_stats

[Lagicrus]

Hey, I don't know if this has been mentioned before, but I was wondering if it made sense to add the "sum" stat into the "env_stats" display during training to help indicate more at a glance how that session went.
Whilst the plethora of numbers you have displayed are great, having one which at a glance gives a indication could be quite useful, or at least that is my two cents