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_plugin.py

@@ -17,6 +17,18 @@ version_added: 1.3.0
 description:
   - This module allows to install, delete, enable and disable Docker plugins.
   - Performs largely the same function as the C(docker plugin) CLI subcommand.
+
+extends_documentation_fragment:
+  - community.docker.docker.api_documentation
+  - community.docker.attributes
+  - community.docker.attributes.actiongroup_docker
+
+attributes:
+  check_mode:
+    support: full
+  diff_mode:
+    support: full
+
 options:
   plugin_name:
     description:
@@ -62,9 +74,6 @@ options:
     type: int
     default: 0
 
-extends_documentation_fragment:
-  - community.docker.docker.api_documentation
-
 author:
   - Sakar Mehra (@sakar97)
   - Vladimir Porshkevich (@porshkevich)