Update documentation (#10696)

* Update documentation

Added to the description explaining the mode of operation and the protocol being used.
This would add to the user experience and saves time for the user.

* use single quotes around colon contained list element to satisfy linter

* Apply suggestions from code review

Co-authored-by: Felix Fontein <felix@fontein.de>

* documentation of nagios module - included all nagios configuration paths in plugins/modules/nagios.py

* used italic code I(...) for paths

* added trailing comma to nagios.cfg path listing

Co-authored-by: Felix Fontein <felix@fontein.de>

* added trailing period after icinga path listing.

Co-authored-by: Felix Fontein <felix@fontein.de>

---------

Co-authored-by: bjt-user <bjoern.foersterling@web.de>
Co-authored-by: Felix Fontein <felix@fontein.de>

plugins/modules/nagios.py

@@ -22,6 +22,13 @@ description:
   - The C(nagios) module is not idempotent.
   - All actions require the O(host) parameter to be given explicitly. In playbooks you can use the C({{inventory_hostname}})
     variable to refer to the host the playbook is currently running on.
+  - The module executes commands and needs to be run directly on the Nagios server
+    with a user that has appropriate access rights. It does not use Nagios' HTTP API.
+  - Searches for a I(nagios.cfg) in I(/etc/nagios), I(/etc/nagios2), I(/etc/nagios3), I(/usr/local/etc/nagios),
+    I(/usr/local/groundwork/nagios/etc), I(/omd/sites/oppy/tmp/nagios), I(/usr/local/nagios/etc),
+    I(/usr/local/nagios), I(/opt/nagios/etc), and I(/opt/nagios),
+    or a I(icinga.cfg) in I(/etc/icinga) and I(/usr/local/icinga/etc).
+    (The Nagios configuration file should be readable by the Ansible user.)
 extends_documentation_fragment:
   - community.general.attributes
 attributes: