Docker: mention Docker SDK for Python instead of docker/docker-py (#53917)

* Mention Docker SDK for Python instead of docker-py / docker.

* Docs fixes.

* Add myself as docker_container author.

* Use array syntax for running command.

* Break long lines.

* Avoid failure when docker_version is None.

* Improve docker-py vs. docker note in requirements.

* Canonicalize Docker SDK for Python upgrade instructions.

* Split long line.

* Make it clearer which hostnames are meant.

lib/ansible/plugins/inventory/docker_swarm.py

@@ -16,7 +16,7 @@ DOCUMENTATION = '''
     short_description: Ansible dynamic inventory plugin for Docker swarm nodes.
     requirements:
         - python >= 2.7
-        - Docker SDK for Python > 1.10.0
+        - L(Docker SDK for Python,https://docker-py.readthedocs.io/en/stable/) >= 1.10.0
     extends_documentation_fragment:
         - constructed
     description:
@@ -24,7 +24,7 @@ DOCUMENTATION = '''
         - Uses a YAML configuration file docker_swarm.[yml|yaml].
     options:
         plugin:
-            description: The name of this plugin, it should always be set to 'docker_swarm' for this plugin to recognize it as it's own.
+            description: The name of this plugin, it should always be set to C(docker_swarm) for this plugin to recognize it as it's own.
             type: str
             required: true
             choices: docker_swarm
@@ -56,7 +56,7 @@ DOCUMENTATION = '''
             description: Path to the client's TLS certificate file.
             type: path
         tls_hostname:
-            description: When verifying the authenticity of the Docker Host server, provide the expected name of the server.
+            description: When verifying the authenticity of the Docker host server, provide the expected name of the server.
             type: str
         ssl_version:
             description: Provide a valid SSL version number. Default value determined by ssl.py module.