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 {