fix: custom jvm options

minecraft/minecraft.nix

@@ -214,13 +214,19 @@ in {
             '';
           };
 
-          customJVMOpts = mkOpt' (
-            with types;
-              coercedTo
-              (listOf str)
-              (lib.concatStringsSep " ")
-              (separatedString " ")
-          ) "" "Custom JVM options for this server.";
+          customJVMOpts = mkOption {
+            description = "Additional JVM options";
+            type = types.coercedTo
+              types.str
+              (lib.splitString " ")
+              (types.listOf types.str);
+            default = [ ];
+            example = [
+              "-Dminecraft.api.env=custom"
+              "-Dminecraft.api.auth.host=https://mcauth.example.space/auth"
+            ];
+          };
+
 
           operators = mkOption {
             type = types.attrsOf (
@@ -379,7 +385,7 @@ in {
               "-Xmx${serverCfg.memory.max}"
               "-Xms${serverCfg.memory.min}"
             ]
-            ++ lib.optional (serverCfg.customJVMOpts != "") serverCfg.customJVMOpts
+      ++ serverCfg.customJVMOpts
           );
 
           autoStart = serverCfg.autoStart;