Manual: Remove some option defaults that refer to store paths

Option defaults should not refer to store paths, because they cause
the manual to be rebuilt gratuitously. It's especially bad to refer to
a highly variable path like a computed configuration file.

nixos/modules/config/pulseaudio.nix

@@ -71,8 +71,7 @@ in {
       };
 
       configFile = mkOption {
-        type = types.uniq types.path;
-        default = "${cfg.package}/etc/pulse/default.pa";
+        type = types.path;
         description = ''
           The path to the configuration the PulseAudio server
           should use. By default, the "default.pa" configuration
@@ -112,6 +111,8 @@ in {
         target = "pulse/client.conf";
         source = clientConf;
       };
+
+      hardware.pulseaudio.configFile = mkDefault "${cfg.package}/etc/pulse/default.pa";
     }
 
     (mkIf cfg.enable {

nixos/modules/services/hardware/pommed.nix

@@ -4,30 +4,34 @@ with lib;
 
 {
 
-  options.services.hardware.pommed = {
-    enable = mkOption {
-      default = false;
-       description = ''
-        Whether to use the pommed tool to handle Apple laptop keyboard hotkeys.
-      '';
+  options = {
+
+    services.hardware.pommed = {
+
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to use the pommed tool to handle Apple laptop keyboard hotkeys.
+        '';
+      };
+
+      configFile = mkOption {
+        type = types.path;
+        description = ''
+          The path to the <filename>pommed.conf</filename> file.
+        '';
+      };
     };
 
-    configFile = mkOption {
-      default = "${pkgs.pommed}/etc/pommed.conf";
-      description = ''
-        The contents of the pommed.conf file.
-      '';
-    };
   };
 
   config = mkIf config.services.hardware.pommed.enable {
     environment.systemPackages = [ pkgs.polkit ];
 
-    environment.etc = [
-      { source = config.services.hardware.pommed.configFile;
-        target = "pommed.conf";
-      }
-    ];
+    environment.etc."pommed.conf".source = config.services.hardware.pommed.configFile;
+
+    services.hardware.pommed.configFile = "${pkgs.pommed}/etc/pommed.conf";
 
     services.dbus.packages = [ pkgs.pommed ];
 

nixos/modules/services/x11/display-managers/default.nix

@@ -169,7 +169,6 @@ in
 
       xserverBin = mkOption {
         type = types.path;
-        default = "${xorg.xorgserver}/bin/X";
         description = "Path to the X server used by display managers.";
       };
 
@@ -280,4 +279,10 @@ in
 
   };
 
+  config = {
+
+    services.xserver.displayManager.xserverBin = "${xorg.xorgserver}/bin/X";
+
+  };
+
 }