Document attributes (#497)

* Add 'docker' action group attribute.

* Compatibility with older ansible-core releases.

* Fix typo.

* Docment standard attributes.

* Improve docs.

* Add shortcuts for common combinations.

plugins/modules/docker_secret.py

@@ -14,13 +14,25 @@ module: docker_secret
 
 short_description: Manage docker secrets.
 
-
 description:
-     - Create and remove Docker secrets in a Swarm environment. Similar to C(docker secret create) and C(docker secret rm).
-     - Adds to the metadata of new secrets C(ansible_key), an encrypted hash representation of the data, which is then used
-       in future runs to test if a secret has changed. If C(ansible_key) is not present, then a secret will not be updated
-       unless the I(force) option is set.
-     - Updates to secrets are performed by removing the secret and creating it again.
+  - Create and remove Docker secrets in a Swarm environment. Similar to C(docker secret create) and C(docker secret rm).
+  - Adds to the metadata of new secrets C(ansible_key), an encrypted hash representation of the data, which is then used
+    in future runs to test if a secret has changed. If C(ansible_key) is not present, then a secret will not be updated
+    unless the I(force) option is set.
+  - Updates to secrets are performed by removing the secret and creating it again.
+
+extends_documentation_fragment:
+  - community.docker.docker
+  - community.docker.docker.docker_py_2_documentation
+  - community.docker.attributes
+  - community.docker.attributes.actiongroup_docker
+
+attributes:
+  check_mode:
+    support: full
+  diff_mode:
+    support: none
+
 options:
   data:
     description:
@@ -81,11 +93,6 @@ options:
       - absent
       - present
 
-extends_documentation_fragment:
-- community.docker.docker
-- community.docker.docker.docker_py_2_documentation
-
-
 requirements:
   - "L(Docker SDK for Python,https://docker-py.readthedocs.io/en/stable/) >= 2.1.0"
   - "Docker API >= 1.25"