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/network/nxos/nxos_ping.py

@@ -43,18 +43,13 @@ options:
     count:
         description:
             - Number of packets to send.
-        required: false
         default: 2
     source:
         description:
             - Source IP Address.
-        required: false
-        default: null
     vrf:
         description:
             - Outgoing VRF.
-        required: false
-        default: null
     state:
         description:
             - Determines if the expected result is success or fail.