Feature request: line which updates obviously to confirm file was reevaluated

[JoshCheek]

Many times now, when showing people a series of refactorings, I rerun the file, but it is not obvious. So then I add something random to make it visually apparent that the file changes. Eg consider this video at 14:40: https://vimeo.com/493957160

I added rand 1000 # => to the bottom of the file to make it clearer that it has actually updated.
Would be nice if there were something built into SiB that could do something visually distinct, possibly with an incrementing number, or possibly some clear change like blinking a big piece of text on/off, each time it runs.