Minor fix to example hook in docs
Minor fix to example hook in docs

mitechie/juju-gui,bac/juju-gui,jrwren/juju-gui,bac/juju-gui,mitechie/juju-gui,bac/juju-gui,mitechie/juju-gui,jrwren/juju-gui,bac/juju-gui,jrwren/juju-gui,mitechie/juju-gui,jrwren/juju-gui