nixos/smartd: Fix mail recipient field

Having undisclosed recipients results in emails being considered spam as mentioned in #192147, by instead identifying the recipient the emails are no longer considered spam

Changed files
+1 -1
nixos
modules
services
monitoring
+1 -1
nixos/modules/services/monitoring/smartd.nix
···
{
${pkgs.coreutils}/bin/cat << EOF
From: smartd on ${host} <${nm.sender}>
-
To: undisclosed-recipients:;
+
To: ${nm.recipient}
Subject: $SMARTD_SUBJECT
$SMARTD_FULLMESSAGE