### What?
This PR makes it easier to use Next.js with IPv6 hostnames such as `::1` and `::`.
### How?
It does so by removing rewrites from `localhost` to `127.0.0.1` introduced in #52492. It also fixes the issue where Next.js tries to fetch something like `http://::1:3000` when `--hostname` is `::1` as it is not a valid URL (browsers' `URL` class throws an error when constructed with such hosts). It also fixes `NextURL` so that it doesn't accept `http://::1:3000` but refuse `http://[::1]:3000`. It also changes `next/src/server/lib/setup-server-worker.ts` so that it uses the server's `address` method to retrieve the host instead of our provided `opts.hostname`, ensuring that no matter what `opts.hostname` is we will always get the correct one.
### Note
I've verified that `next dev`, `next start` and `node .next/standalone/server.js` work with IPv6 hostnames (such as `::` and `::1`), IPv4 hostnames (such as `127.0.0.1`, `0.0.0.0`) and `localhost` - and with any of these hostnames fetching to `localhost` also works. Server Actions and middleware have no problems as well.
This also removes `.next/standalone/server.js`'s logging as we now use `start-server`'s logging to avoid duplicates. `start-server`'s logging has also been updated to report the actual hostname.
The above pictures also demonstrate using Server Actions with Next.js after this PR.
Fixes#53171Fixes#49578
Closes NEXT-1510
Co-authored-by: Tim Neutkens <6324199+timneutkens@users.noreply.github.com>
Co-authored-by: Zack Tanner <1939140+ztanner@users.noreply.github.com>
a4b430e6f1