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_nova_flavor.py

@@ -28,7 +28,6 @@ options:
           then I(ram), I(vcpus), and I(disk) are all required. There are no
           default values for those parameters.
      choices: ['present', 'absent']
-     required: false
      default: present
    name:
      description:
@@ -37,53 +36,40 @@ options:
    ram:
      description:
         - Amount of memory, in MB.
-     required: false
-     default: null
    vcpus:
      description:
         - Number of virtual CPUs.
-     required: false
-     default: null
    disk:
      description:
         - Size of local disk, in GB.
-     required: false
-     default: null
    ephemeral:
      description:
         - Ephemeral space size, in GB.
-     required: false
      default: 0
    swap:
      description:
         - Swap space size, in MB.
-     required: false
      default: 0
    rxtx_factor:
      description:
         - RX/TX factor.
-     required: false
      default: 1.0
    is_public:
      description:
         - Make flavor accessible to the public.
-     required: false
-     default: true
+     type: bool
+     default: 'yes'
    flavorid:
      description:
         - ID for the flavor. This is optional as a unique UUID will be
           assigned if a value is not specified.
-     required: false
      default: "auto"
    availability_zone:
      description:
        - Ignored. Present for backwards compatibility
-     required: false
    extra_specs:
      description:
         - Metadata dictionary
-     required: false
-     default: None
      version_added: "2.3"
 requirements: ["shade"]
 '''