[PATCH 2 of 5 v2] graft: suggest the correct tool to continue (not graft)

[timeless]

Pierre-Yves David wrote:
> no "graft state found" is not super clear for a end user as it expose some
> internal details. You used "no XXX in progress" for the other action, I
> think we should use it here too.

Oh, I definitely choked when I saw that, but it isn't me.
I just didn't want to lengthen the series to fix that too.

I'm +1 on fixing it.