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/packaging/language/pear.py

@@ -34,14 +34,11 @@ options:
     state:
         description:
             - Desired state of the package.
-        required: false
         default: "present"
         choices: ["present", "absent", "latest"]
     executable:
       description:
         - Path to the pear executable
-      required: false
-      default: null
       version_added: "2.4"
 '''