bug#36698: shepherd: list-actions not implemented

[Brice Waegeneire]

> I am curious about what actions are implemented in the system services
> on my GuixSD install. I try something like the following for the
> different system services and get an error:
>
> jesse@piranhaplant ~$ sudo herd list-actions term-tty6
> Password:
> herd: service 'term-tty6' does not have an action 'list-actions'

The documentation has been updated in 
d5da712a5605a0cdaa4cf3bd64621a95a54520c0
to clarify the use of 'list-actions' and there is an example on how to 
use it.

# herd doc term-tty6 list-actions
term-tty6 ()
# herd doc root list-actions
root (help status halt power-off load eval unload reload daemonize 
persistency no-persistency cd restart)

This bug should be closed.