Update `next/server` documentation for `geo` (#33609)
Update `next/server` documentation for `geo` (#33609)

Make it clear that `geo` is not populated by the default Next.js server, and requires your hosting platform to integrate with a geolocation service to look up the location based on the request.

If self-hosting, for example, this could be achieved with the [Google Geolocation API](https://developers.google.com/maps/documentation/geolocation/overview).
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