[Feature]: Nvm ls without any installed versions should tell you how to get them

[frederikja163]

Description of the new feature / enhancement

Would be nice if running nvm ls without any installations would tell you to run nvm install latest

Could also make this message in other commands when running at first.

Scenario when this would be used?

When you install nvm at first it is a bit hard finding out how to install a version at first

Supporting information

nvm on already does this

> nvm on
nvm enabled
No versions of node.js found. Try installing the latest by typing nvm install latest

[coreybutler]

I figured nvm --help would be enough, but this could still be a nice enchancement.

If I think of it, I'll add a note to nvm ls. Realistically, it probably won't happen though - it's just not high priority when there are so many examples of how to get started. Runtime, the successor project, is almost done. There's a few GUI features in it addressing the setup of a new environment.

I'll keep this open so I review it prior to the next release.