Potential new rule: only call internal_export'ed functions from test code

[paulo-ferraz-oliveira]

This issue might evolve into a new rule proposal, after which I'll update the description accordingly.

If erlang/otp#7407 goes forward, do you think Elvis would have a say on (what appears to be) "test" code being called from "non-test" code. We could have the rule disabled by default but suggested for use with the "test" folder (?)

Thoughts?

[elbrujohalcon]

I like the idea, but wouldn't that be covered already by the XRef changes proposed in that same PR?

[paulo-ferraz-oliveira]

Maybe (?) We can wait until it comes out, then test it and see if we need to do something about it :)