Description

In the doc right now we document jaas commands as:

Usage
jaas show-model [options] <model>

This is not correct because you can't run jaas commands by itself, and you need to run them via juju.

I've tried to use:

jaasCmd := jujucmd.NewSuperCommand(jujucmd.SuperCommandParams{
		Name: "jaas",
		Doc:  jaasDoc,
               	UsagePrefix: "juju"
	})

the problem is that UsagePrefix is not used to generate documentation, so the easier thing was just to amend our generate script to fix the doc.