message: Improve docs: Add payment setting doc
diff: @@ -441,6 +441,21 @@ Remove the home_url setting
  Get the home_url
  +### controller.api.messenger_profile.payment_settings()
  +| Argument | Description
  +|--- |---
  +| payload | A JSON object with the properties `privacy_url`, `public_key`, `testers`
  +
  +View [the facebook documentation](https://developers.facebook.com/docs/messenger-platform/reference/messenger-profile-api/payment-settings) for more details.
  +
  +### controller.api.messenger_profile.delete_payment_settings()
  +
  +Remove the payment_settings setting
  +
  +### controller.api.messenger_profile.get_payment_settings()
  +
  +Get the payment_settings property of your bot's Messenger Profile
  +
  #### Using the The Messenger Profile API
  ```js
  