resizer.enabled is confusing and undocumented

I expected akka.actor.deployment.router.resizer.enabled = off would disable the resizer, but it doesn't appear to. I have to remove the entire section to disable. (Granted, it says so in the docs). But what is "enabled" for then?

from ktoso: some legacy reasons i guess

It's a bit confusing to have enabled = on (without any comments) in reference.conf since it suggests that you could use it to turn the resizer on/off.

If it doesn't do anything then the flag should probably be removed, or it should actually work. But barring that, a comment in reference.conf to clarify would help remove any confusion.

Also optimal-size-exploring-resizer.