services/misc/nixos-manual.nix: Remove

Running the manual on a TTY is useless in the graphical ISOs and not
particularly useful in non-graphical ISOs (since you can also run
'nixos-help').

Fixes #83157.

nixos/modules/services/misc/nixos-manual.nix

@@ -1,73 +0,0 @@
-# This module optionally starts a browser that shows the NixOS manual
-# on one of the virtual consoles which is useful for the installation
-# CD.
-
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-  cfg = config.services.nixosManual;
-  cfgd = config.documentation;
-in
-
-{
-
-  options = {
-
-    # TODO(@oxij): rename this to `.enable` eventually.
-    services.nixosManual.showManual = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-        Whether to show the NixOS manual on one of the virtual
-        consoles.
-      '';
-    };
-
-    services.nixosManual.ttyNumber = mkOption {
-      type = types.int;
-      default = 8;
-      description = ''
-        Virtual console on which to show the manual.
-      '';
-    };
-
-    services.nixosManual.browser = mkOption {
-      type = types.path;
-      default = "${pkgs.w3m-nographics}/bin/w3m";
-      description = ''
-        Browser used to show the manual.
-      '';
-    };
-
-  };
-
-
-  config = mkMerge [
-    (mkIf cfg.showManual {
-      assertions = singleton {
-        assertion = cfgd.enable && cfgd.nixos.enable;
-        message   = "Can't enable `services.nixosManual.showManual` without `documentation.nixos.enable`";
-      };
-    })
-    (mkIf (cfg.showManual && cfgd.enable && cfgd.nixos.enable) {
-      console.extraTTYs = [ "tty${toString cfg.ttyNumber}" ];
-
-      systemd.services.nixos-manual = {
-        description = "NixOS Manual";
-        wantedBy = [ "multi-user.target" ];
-        serviceConfig = {
-          ExecStart = "${cfg.browser} ${config.system.build.manual.manualHTMLIndex}";
-          StandardInput = "tty";
-          StandardOutput = "tty";
-          TTYPath = "/dev/tty${toString cfg.ttyNumber}";
-          TTYReset = true;
-          TTYVTDisallocate = true;
-          Restart = "always";
-        };
-      };
-    })
-  ];
-
-}