Mention docker[tls]. (#49095) (#49153)

(cherry picked from commit be55abafe1)

lib/ansible/utils/module_docs_fragments/docker.py

@@ -104,5 +104,7 @@ notes:
       You can define DOCKER_HOST, DOCKER_TLS_HOSTNAME, DOCKER_API_VERSION, DOCKER_CERT_PATH, DOCKER_SSL_VERSION,
       DOCKER_TLS, DOCKER_TLS_VERIFY and DOCKER_TIMEOUT. If you are using docker machine, run the script shipped
       with the product that sets up the environment. It will set these variables for you. See
-      https://docker-py.readthedocs.io/en/stable/machine/ for more details.
+      U(https://docker-py.readthedocs.io/en/stable/machine/) for more details.
+    - When connecting to Docker daemon with TLS, you might need to install additional Python packages.
+      For the Docker SDK for Python, version 2.4 or newer, this can be done by installing C(docker[tls]) with M(pip).
 '''