Apply suggestions from aidalgol#14

Author: hamburger1984

nixos-modules/valheim.nix

@@ -72,24 +72,8 @@ in {
       '';
     };
 
-    logFile = lib.mkOption {
-      type = with lib.types; nullOr str;
-      default = null;
-      example = "/var/lib/valheim/log/valheim-server.log";
-      description = lib.mdDoc ''
-        The path where the server log file will be saved.
-
-        When set, this will redirect all logs from stdout to the specified path.
-        This means that the logs will not be captured by systemd's journal.
-        Leave this option unset to keep console logging enabled.
-
-        Make sure the valheim user has write access to the specified directory, otherwise
-        the valheim service fail to start and exit.
-      '';
-    };
-
     preset = lib.mkOption {
-      type = with lib.types; nullOr str;
+      type = with lib.types; nullOr (enum ["easy" "hard" "hardcore" "casual" "hammer" "immersive"]);
       default = null;
       example = "hardcore";
       description = lib.mdDoc ''
@@ -317,7 +301,6 @@ in {
                 "-public ${if cfg.public then "1" else "0"}"
               ]
               ++ (lib.lists.optional cfg.crossplay "-crossplay")
-              ++ (lib.lists.optional (cfg.logFile != null) "-logFile \"${cfg.logFile}\"")
               ++ (lib.lists.optional (cfg.preset != null) "-preset \"${cfg.preset}\""));
         };
       };