nixos/grub: Add extraEntriesAtEnd

[NazakatUmrani]

This option allows the user to specify a list of extra entries to be added to the end of the grub menu.

Description of changes

I added this new option as boot.loader.grub.extraEntriesAtEnd, This option adds entries at the end of grub, The normal extraEntries option adds entries in the middle of NixOS and NixOS-Generations entry.

I wanted to add shutdown and reboot entries and end, but that old option was never designed to do that, so I created this new option which runs after OS Prober, and after OS Prober adds those entries then from this option entries are taken.

Things done

I added an option with its description.
I added that option in the Perl file, after the line where OS Prober entries are loaded.

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

My Message

I have never worked with Perl, but I am a student studying software engineering, and I used GitHub Copilot, so it may or may not contain bugs, please check it, I want this option as I am frustrated with the old option and it's arrangement, so please add it.

[NazakatUmrani]

For those who are facing same issue, I used extraInstallCommands option for now, this edits the grub file, after it is generated by perl file

boot.loader.grub.extraInstallCommands =  ''
cat << EOF >> /boot/grub/grub.cfg

# Shutdown
menuentry "Shutdown" --class shutdown {
  halt
}

# Reboot
menuentry "Reboot" --class restart{
  reboot
}
EOF
   '';

It works, it appends those entries in the file, but editing file like this, you should be careful.