Clean up module documentation (#36909)

* Clean up module documentation

This PR includes:
- Removal of `default: None` (and variations)
- Removal of `required: false`
- Fixing booleans and `type: bool` where required

* Fix remaining (new) validation issues

lib/ansible/modules/cloud/openstack/os_server_volume.py

@@ -40,12 +40,9 @@ options:
    device:
      description:
       - Device you want to attach. Defaults to auto finding a device name.
-     required: false
-     default: None
    availability_zone:
      description:
        - Ignored. Present for backwards compatibility
-     required: false
 requirements:
     - "python >= 2.6"
     - "shade"