Added note on netcat dependency (#24070)

Originally https://github.com/ansible/ansible/pull/23911/files

lib/ansible/modules/net_tools/haproxy.py

@@ -36,7 +36,9 @@ notes:
     - Enable and disable commands are restricted and can only be issued on
       sockets configured for level 'admin'. For example, you can add the line
       'stats socket /var/run/haproxy.sock level admin' to the general section of
-      haproxy.cfg. See http://haproxy.1wt.eu/download/1.5/doc/configuration.txt.
+      haproxy.cfg. See U(http://haproxy.1wt.eu/download/1.5/doc/configuration.txt).
+    - Depends on netcat (nc) being available; you need to install the appriate
+      package for your operating system before this module can be used.
 options:
   backend:
     description: