ansible/changelogs/fragments/allow-fail-json-msg-to-be-positional.yaml

minor_changes:
  - "`AnsibleModule.fail_json()` has always required that a message be passed
    in which informs the end user why the module failed.  In the past this
    message had to be passed as the `msg` keyword argument but it can now be
    passed as the first positional argument instead."