A composable which observes the page title changes and updates the announcer message accordingly. Used by [`<NuxtRouteAnnouncer>`](/docs/api/components/nuxt-route-announcer) and controllable.
It hooks into Unhead's [`dom:rendered`](https://unhead.unjs.io/api/core/hooks#dom-hooks) to read the page's title and set it as the announcer message.
## Parameters
-`politeness`: Sets the urgency for screen reader announcements: `off` (disable the announcement), `polite` (waits for silence), or `assertive` (interrupts immediately). (default `polite`).