Install nix-manual in default user profile

This makes man pages available in the default profile after using nix
installer.

Relates to: #12382

Author: koberbe-jh

packaging/binary-tarball.nix

@@ -4,13 +4,15 @@
   buildPackages,
   cacert,
   nix,
+  nixComponents2,
 }:
 
 let
 
   installerClosureInfo = buildPackages.closureInfo {
     rootPaths = [
       nix
+      nixComponents2.nix-manual.man
       cacert
     ];
   };
@@ -42,6 +44,7 @@ runCommand "nix-binary-tarball-${version}" env ''
     --subst-var-by cacert ${cacert}
   substitute ${../scripts/install-multi-user.sh} $TMPDIR/install-multi-user \
     --subst-var-by nix ${nix} \
+    --subst-var-by nix-manual ${nixComponents2.nix-manual.man}
     --subst-var-by cacert ${cacert}
 
   if type -p shellcheck; then

scripts/install-multi-user.sh

@@ -52,6 +52,7 @@ readonly PROFILE_FISH_PREFIXES=(
 readonly PROFILE_NIX_FILE_FISH="$NIX_ROOT/var/nix/profiles/default/etc/profile.d/nix-daemon.fish"
 
 readonly NIX_INSTALLED_NIX="@nix@"
+readonly NIX_INSTALLED_NIX_MAN="@nix-manual@"
 readonly NIX_INSTALLED_CACERT="@cacert@"
 #readonly NIX_INSTALLED_NIX="/nix/store/byi37zv50wnfrpp4d81z3spswd5zva37-nix-2.3.6"
 #readonly NIX_INSTALLED_CACERT="/nix/store/7pi45g541xa8ahwgpbpy7ggsl0xj1jj6-nss-cacert-3.49.2"
@@ -969,6 +970,8 @@ setup_default_profile() {
     task "Setting up the default profile"
     _sudo "to install a bootstrapping Nix in to the default profile" \
           HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_NIX"
+    _sudo "to install Nix man pages in to the default profile" \
+          HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_NIX_MAN"
 
     if [ -z "${NIX_SSL_CERT_FILE:-}" ] || ! [ -f "${NIX_SSL_CERT_FILE:-}" ] || cert_in_store; then
         _sudo "to install a bootstrapping SSL certificate just for Nix in to the default profile" \