Merge pull request #5555 from cheeseprocedure/docs-communicator-ssh-agent

Website: add ssh_agent_auth to ssh communicator docs

website/source/docs/templates/communicator.html.md

@@ -52,12 +52,16 @@ configuration parameters for that communicator. These are documented below.
 
 ## SSH Communicator
 
-The SSH communicator connects to the host via SSH. If you have an SSH
-agent enabled on the machine running Packer, it will automatically forward
-the SSH agent to the remote host.
+The SSH communicator connects to the host via SSH. If you have an SSH agent
+configured on the host running Packer, and SSH agent authentication is enabled
+in the communicator config, Packer will automatically forward the SSH agent
+to the remote host.
 
 The SSH communicator has the following options:
 
+-   `ssh_agent_auth` (boolean) - If true, the local SSH agent will be used to
+    authenticate connections to the remote host. Defaults to false.
+
 -   `ssh_bastion_agent_auth` (boolean) - If true, the local SSH agent will
     be used to authenticate with the bastion host. Defaults to false.