message: docs(loading): add accessibility section
diff: @@ -125,6 +125,13 @@ import Theming from '@site/static/usage/loading/theming/index.md';
  `ion-loading` is presented at the root of your application, so we recommend placing any `ion-loading` styles in a global stylesheet.
  :::
  +## Accessibility
  +
  +Ionic automatically sets Loading's `role` to [`dialog`](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/dialog_role).
  +
  +If the `message` property is defined for Loading, then the `aria-labelledby` attribute will be automatically set to the message element's ID. Otherwise, `aria-labelledby` will not be set, and developers must provide an `aria-label` using the `htmlAttributes` property.
  +
  +All ARIA attributes can be manually overwritten by defining custom values in the `htmlAttributes` property of Loading.
  ## Interfaces
  