[#1841] Escaping curly braces in MessageBundle (#1842)

Without escaping `MessageFormatter` is unable to process the message.

---------

Co-authored-by: Benjamin Asbach <asbachb@users.noreply.github.com>

Author: asbachb

jaxb-ri/xjc/src/main/resources/com/sun/tools/xjc/generator/bean/field/MessageBundle.properties

@@ -27,7 +27,7 @@ DEFAULT_GETTER_LIST_JAVADOC = \
         <p>This accessor method returns a reference to the live list,\n\
         not a snapshot. Therefore any modification you make to the\n\
         returned list will be present inside the Jakarta XML Binding object.\n\
-        This is why there is not a {@code set} method for the {0} property.</p>\n\n\
+        This is why there is not a '{'@code set'}' method for the {0} property.</p>\n\n\
         <p>\n\
         For example, to add a new item, do as follows:\n\
         </p>\n\

jaxb-ri/xjc/src/test/java/com/sun/tools/xjc/XjcDtdPluginTest.java

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2025 Contributors to the Eclipse Foundation. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Distribution License v. 1.0, which is available at
@@ -81,4 +82,24 @@ public void postProcessModel(Model model, ErrorHandler errorHandler) {
             wasPostProcessModelHookCalled[0]
         );
     }
+
+    @Test
+    public void testIssue_cannotRenderJavadocForLists() throws Exception {
+        final OptionsEx opt = new OptionsEx();
+        opt.setSchemaLanguage(Language.DTD);
+        opt.compatibilityMode = Options.EXTENSION;
+
+        opt.addGrammar(
+            new InputSource(
+                new ByteArrayInputStream("<!ELEMENT AnElement1 (#PCDATA)>\n<!ELEMENT AnElement2 (#PCDATA)>\n<!ELEMENT AnElement (AnElement1 | AnElement2)>".getBytes())
+            )
+        );
+
+        Model model = ModelLoader.load(
+            opt,
+            new JCodeModel(),
+            null
+        );
+        model.generateCode(opt, null);
+    }
 }