message: add links to w3c
diff: @@ -20,6 +20,10 @@ Behaviors include:
  - A value set for the `aria-labelledby` attribute that refers to a visible title.
  - An `aria-label` attribute
  - If the `Overlay` should also have a longer description, use `aria-describedby`
  +- The `Overlay` component has a `role="dialog"` set on it, if you are using `Overlay` for alerts, you can pass in `role="alertdialog" instead. Please read the [W3C guidelines](https://www.w3.org/TR/wai-aria-1.1/#alertdialog) to determine which role is best for your use case
  +- The `Overlay` component has `aria-modal` set to `true` by default and should not be overridden as all `Overlay`s behave as modals.
  +
  +See the W3C accessibility recommendations for modals [here](https://www.w3.org/TR/wai-aria-practices-1.1/#dialog_roles_states_props).
  ## Default example
  