Updated documentation to reflect new behaviour (#7685)

* Updated documentation to reflect new behaviour

Per issue [6027](https://github.com/ansible-collections/community.general/issues/6027), disk and storage should not be used together, and changes to the API make it so "disk" should be formatted like "<storage>:<size in gb>".

Documentation edited to reflect this new behavior.

* Apply suggestions from code review

Change format due to referencing options.

Co-authored-by: Felix Fontein <felix@fontein.de>

---------

Co-authored-by: Felix Fontein <felix@fontein.de>

plugins/modules/proxmox.py

@@ -48,6 +48,7 @@ options:
         [,replicate=<1|0>] [,ro=<1|0>] [,shared=<1|0>] [,size=<DiskSize>])."
       - See U(https://pve.proxmox.com/wiki/Linux_Container) for a full description.
       - This option has no default unless O(proxmox_default_behavior) is set to V(compatibility); then the default is V(3).
+      - Should not be used in conjunction with O(storage).
     type: str
   cores:
     description:
@@ -96,6 +97,7 @@ options:
   storage:
     description:
       - target storage
+      - Should not be used in conjunction with O(disk).
     type: str
     default: 'local'
   ostype:
@@ -248,6 +250,18 @@ EXAMPLES = r'''
     hostname: example.org
     ostemplate: 'local:vztmpl/ubuntu-14.04-x86_64.tar.gz'
 
+- name: Create new container with minimal options specifying disk storage location and size
+  community.general.proxmox:
+    vmid: 100
+    node: uk-mc02
+    api_user: root@pam
+    api_password: 1q2w3e
+    api_host: node1
+    password: 123456
+    hostname: example.org
+    ostemplate: 'local:vztmpl/ubuntu-14.04-x86_64.tar.gz'
+    disk: 'local-lvm:20'
+
 - name: Create new container with hookscript and description
   community.general.proxmox:
     vmid: 100