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/rackspace/rax_files_objects.py

@@ -24,15 +24,12 @@ options:
     description:
       - Optionally clear existing metadata when applying metadata to existing objects.
         Selecting this option is only appropriate when setting type=meta
-    choices:
-      - "yes"
-      - "no"
-    default: "no"
+    type: bool
+    default: 'no'
   container:
     description:
       - The container to use for file object operations.
     required: true
-    default: null
   dest:
     description:
       - The destination of a "get" operation; i.e. a local directory, "/home/user/myfolder".
@@ -42,11 +39,9 @@ options:
     description:
       - Used to set an expiration on a file or folder uploaded to Cloud Files.
         Requires an integer, specifying expiration in seconds
-    default: null
   meta:
     description:
       - A hash of items to set as metadata values on an uploaded file or folder
-    default: null
   method:
     description:
       - The method of operation to be performed.  For example, put to upload files
@@ -62,16 +57,13 @@ options:
       - Source from which to upload files.  Used to specify a remote object as a source for
         an operation, i.e. a file name, "file1", or a comma-separated list of remote objects,
         "file1,file2,file17".  src and dest are mutually exclusive on remote-only object operations
-    default: null
   structure:
     description:
       - Used to specify whether to maintain nested directory structure when downloading objects
         from Cloud Files.  Setting to false downloads the contents of a container to a single,
         flat directory
-    choices:
-      - yes
-      - "no"
-    default: "yes"
+    type: bool
+    default: 'yes'
   state:
     description:
       - Indicate desired state of the resource