add_hosts.py: Fix add_host does not recognise 'host' alias (#27418)

* add_hosts.py: Fix add_host does not recognise 'host' alias

* add_hosts.py: add note in documentation that 'hosts' alias of name parameter is only available on >=2.4

lib/ansible/modules/inventory/add_host.py

@@ -44,6 +44,7 @@ notes:
     - This module bypasses the play host loop and only runs once for all the hosts in the play, if you need it
       to iterate use a with\_ directive.
     - This module is also supported for Windows targets.
+    - The alias 'host' of the parameter 'name' is only available on >=2.4
 author:
     - "Ansible Core Team"
     - "Seth Vidal"

lib/ansible/plugins/action/add_host.py

@@ -46,7 +46,7 @@ class ActionModule(ActionBase):
         result = super(ActionModule, self).run(tmp, task_vars)
 
         # Parse out any hostname:port patterns
-        new_name = self._task.args.get('name', self._task.args.get('hostname', None))
+        new_name = self._task.args.get('name', self._task.args.get('hostname', self._task.args.get('host', None)))
         display.vv("creating host via 'add_host': hostname=%s" % new_name)
 
         try: