It makes some sense to want to know this. You might know that your build process doesn't benefit from more than 4 jobs, and want to alert this to the developer who tries to use more.
I really have to echo the person who replied to you on a different thread and ask.. why? What do you think you're saving the user from exactly?
Please avoid such things. Useless warnings just create noise that mask real ones. Just this one may not matter, but the same rationality would apply to hundreds more.