docs: mention Connect ACLs guide in jobspec connect docs
docs: mention Connect ACLs guide in jobspec connect docs

Promote the Connect ACLs guide on the jobspec connect stanza docs
page. This was suggested in a ticket after someone got stuck not
realizing they needed to enable Consul Intentions for their connect
enabled services, which is covered in the guide.

burdandrei/nomad,burdandrei/nomad,dvusboy/nomad,burdandrei/nomad,burdandrei/nomad,burdandrei/nomad,hashicorp/nomad,dvusboy/nomad,dvusboy/nomad,dvusboy/nomad,dvusboy/nomad,burdandrei/nomad,hashicorp/nomad,hashicorp/nomad,dvusboy/nomad,hashicorp/nomad,hashicorp/nomad,dvusboy/nomad,hashicorp/nomad,burdandrei/nomad