Make clear that inventory config files need to have a very speific ending. (#974)

plugins/inventory/docker_containers.py

@@ -12,7 +12,7 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 
-DOCUMENTATION = '''
+DOCUMENTATION = r'''
 name: docker_containers
 short_description: Ansible dynamic inventory plugin for Docker containers
 version_added: 1.1.0
@@ -25,7 +25,11 @@ extends_documentation_fragment:
     - community.library_inventory_filtering_v1.inventory_filter
 description:
     - Reads inventories from the Docker API.
-    - Uses a YAML configuration file that ends with C(docker.[yml|yaml]).
+    - Uses a YAML configuration file that ends with V(docker.(yml|yaml\)).
+notes:
+    - The configuration file must be a YAML file whose filename ends with V(docker.yml) or V(docker.yaml).
+      Other filenames will not be accepted.
+
 options:
     plugin:
         description:

plugins/inventory/docker_machine.py

@@ -6,7 +6,7 @@
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
-DOCUMENTATION = '''
+DOCUMENTATION = r'''
     name: docker_machine
     author: Ximon Eighteen (@ximon18)
     short_description: Docker Machine inventory source
@@ -17,9 +17,12 @@ DOCUMENTATION = '''
         - community.library_inventory_filtering_v1.inventory_filter
     description:
         - Get inventory hosts from Docker Machine.
-        - Uses a YAML configuration file that ends with docker_machine.(yml|yaml).
+        - Uses a YAML configuration file that ends with V(docker_machine.(yml|yaml\)).
         - The plugin sets standard host variables C(ansible_host), C(ansible_port), C(ansible_user) and C(ansible_ssh_private_key).
         - The plugin stores the Docker Machine 'env' output variables in C(dm_) prefixed host variables.
+    notes:
+        - The configuration file must be a YAML file whose filename ends with V(docker_machine.yml) or V(docker_machine.yaml).
+          Other filenames will not be accepted.
 
     options:
         plugin:

plugins/inventory/docker_swarm.py

@@ -8,7 +8,7 @@ from __future__ import (absolute_import, division, print_function)
 
 __metaclass__ = type
 
-DOCUMENTATION = '''
+DOCUMENTATION = r'''
     name: docker_swarm
     author:
       - Stefan Heitmüller (@morph027) <stefan.heitmueller@gmx.com>
@@ -21,10 +21,14 @@ DOCUMENTATION = '''
         - community.library_inventory_filtering_v1.inventory_filter
     description:
         - Reads inventories from the Docker swarm API.
-        - Uses a YAML configuration file docker_swarm.[yml|yaml].
+        - Uses a YAML configuration file that ends with V(docker_swarm.(yml|yaml\)).
         - "The plugin returns following groups of swarm nodes:  C(all) - all hosts; C(workers) - all worker nodes;
           C(managers) - all manager nodes; C(leader) - the swarm leader node;
           C(nonleaders) - all nodes except the swarm leader."
+    notes:
+        - The configuration file must be a YAML file whose filename ends with V(docker_swarm.yml) or V(docker_swarm.yaml).
+          Other filenames will not be accepted.
+
     options:
         plugin:
             description: The name of this plugin, it should always be set to V(community.docker.docker_swarm)