nixos-rebuild: Include manual page in the package

pkgs/os-specific/linux/nixos-rebuild/default.nix

@@ -6,6 +6,7 @@
 , nix
 , lib
 , nixosTests
+, installShellFiles
 }:
 let
   fallback = import ./../../../../nixos/modules/installer/tools/nix-fallback-paths.nix;
@@ -20,6 +21,12 @@ substituteAll {
   nix_i686_linux = fallback.i686-linux;
   nix_aarch64_linux = fallback.aarch64-linux;
   path = lib.makeBinPath [ coreutils gnused gnugrep ];
+  nativeBuildInputs = [
+    installShellFiles
+  ];
+  postInstall = ''
+    installManPage ${./nixos-rebuild.8}
+  '';
 
   # run some a simple installer tests to make sure nixos-rebuild still works for them
   passthru.tests = {