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/amazon/ec2_vpc_dhcp_option.py

@@ -35,38 +35,26 @@ options:
   domain_name:
     description:
       - The domain name to set in the DHCP option sets
-    required: false
-    default: None
   dns_servers:
     description:
       - A list of hosts to set the DNS servers for the VPC to. (Should be a
         list of IP addresses rather than host names.)
-    required: false
-    default: None
   ntp_servers:
     description:
       - List of hosts to advertise as NTP servers for the VPC.
-    required: false
-    default: None
   netbios_name_servers:
     description:
       - List of hosts to advertise as NetBIOS servers.
-    required: false
-    default: None
   netbios_node_type:
     description:
       - NetBIOS node type to advertise in the DHCP options.
         The AWS recommendation is to use 2 (when using netbios name services)
         http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_DHCP_Options.html
-    required: false
-    default: None
   vpc_id:
     description:
       - VPC ID to associate with the requested DHCP option set.
         If no vpc id is provided, and no matching option set is found then a new
         DHCP option set is created.
-    required: false
-    default: None
   delete_old:
     description:
       - Whether to delete the old VPC DHCP option set when associating a new one.
@@ -74,21 +62,19 @@ options:
         want to quickly roll back to the old option set. Note that this setting
         will be ignored, and the old DHCP option set will be preserved, if it
         is in use by any other VPC. (Otherwise, AWS will return an error.)
-    required: false
-    default: true
+    type: bool
+    default: 'yes'
   inherit_existing:
     description:
       - For any DHCP options not specified in these parameters, whether to
         inherit them from the options set already applied to vpc_id, or to
         reset them to be empty.
-    required: false
-    default: false
+    type: bool
+    default: 'no'
   tags:
     description:
       - Tags to be applied to a VPC options set if a new one is created, or
         if the resource_id is provided. (options must match)
-    required: False
-    default: None
     aliases: [ 'resource_tags']
     version_added: "2.1"
   dhcp_options_id:
@@ -96,15 +82,12 @@ options:
       - The resource_id of an existing DHCP options set.
         If this is specified, then it will override other settings, except tags
         (which will be updated to match)
-    required: False
-    default: None
     version_added: "2.1"
   state:
     description:
       - create/assign or remove the DHCP options.
         If state is set to absent, then a DHCP options set matched either
         by id, or tags and options will be removed if possible.
-    required: False
     default: present
     choices: [ 'absent', 'present' ]
     version_added: "2.1"