nixos/systemd: drop kbrequest.target symlink

nixos/doc/manual/release-notes/rl-2511.section.md

@@ -153,6 +153,8 @@
 
 - `command-not-found` package is now disabled by default; it works only for nix-channels based systems, and requires setup for it to work.
 
+- The systemd target `kbrequest.target` is now unset by default, instead of being forcibly symlinked to `rescue.target`. In case you were relying on this behavior (Alt + ArrowUp on the tty causing the current target to be changed to `rescue.target`), you can restore it by setting `systemd.targets.rescue.aliases = [ "kbrequest.target" ];` in your configuration.
+
 ## Other Notable Changes {#sec-release-25.11-notable-changes}
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->

nixos/lib/systemd-lib.nix

@@ -524,7 +524,6 @@ rec {
           # Stupid misc. symlinks.
           ln -s ${cfg.defaultUnit} $out/default.target
           ln -s ${cfg.ctrlAltDelUnit} $out/ctrl-alt-del.target
-          ln -s rescue.target $out/kbrequest.target
 
           ln -s ../remote-fs.target $out/multi-user.target.wants/
         ''}