clarify the use of the variable

Co-authored-by: schurzi <[email protected]>

roles/icinga_agent/README.md

@@ -11,7 +11,7 @@ This role installs and configures the icinga agent.
 | icinga_agent_ca_host | no | | your master instance (f.e: master0-example.de)
 | icinga_agent_ca_host_icinga_port | no | 5665 | Icinga agent port
 | icinga_agent_salt | no | | used to hash password
-| icinga_agent_hostname | no | "{{ ansible_hostname }}" | define hostname (use `ansible_fqdn` for icinga satellites)
+| icinga_agent_hostname | no | "{{ ansible_hostname }}" | define hostname (icinga satellites require this to be set to `ansible_fqdn` or some other usable FQDN)
 | icinga_agent_custom_features_template_path | no | | define custom feature file (f.e. {{ playbook_dir }}/icinga_custom_templates/*)
 | icinga_agent_constants[RedHat, Debian] | yes | const PluginDir = "/usr/lib64/nagios/plugins"<br> const PluginContribDir = "/usr/lib64/nagios/plugins"<br> const ManubulonPluginDir = "/usr/lib64/nagios/plugins"<br> const ZoneName = "{{ ansible_hostname }}"<br> const NodeName = "{{ ansible_hostname }}"<br> const TicketSalt = "" | define content for config file constants.conf, depending on the OS family |
 | icinga_agent_api_conf | yes | accept_config = true<br>accept_commands = true | define content for feature file api.conf |