Debian repository lacks Release file compatible with Debian ≥ 13

The current instructions for installing on Debian failed for me. Debian gives me the following error if I try to sudo apt update after following the instructions on the website (click):

Error: The repository 'http://openresty.org/package/debian trixie Release' does not have a Release file.
Notice: Updating from such a repository can't be done securely, and is therefore disabled by default.
Notice: See apt-secure(8) manpage for repository creation and user configuration details.

This was attempted on a distrobox image running Debian GNU/Linux 13 (trixie). On a distrobox image running Debian GNU/Linux 12 (bookworm), it works fine, but contains the warning:

W: http://openresty.org/package/debian/dists/bookworm/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.

So I'm guessing Debian changed how they handle keyrings and the repository needs to be updated to work with Debian Unstable and Testing.