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_prune.py

@@ -18,6 +18,16 @@ description:
   - Allows to run C(docker container prune), C(docker image prune), C(docker network prune)
     and C(docker volume prune) via the Docker API.
 
+extends_documentation_fragment:
+  - community.docker.docker.api_documentation
+  - community.docker.attributes
+  - community.docker.attributes.actiongroup_docker
+
+attributes:
+  check_mode:
+    support: none
+  diff_mode:
+    support: none
 
 options:
   containers:
@@ -72,10 +82,6 @@ options:
     type: bool
     default: false
 
-extends_documentation_fragment:
-  - community.docker.docker.api_documentation
-
-
 author:
   - "Felix Fontein (@felixfontein)"