Add serialization hint for ProblemDetail

Prior to this commit, a Spring web application would not be able to
serialize a `ProblemDetail` object instance in a Native Image, as
serialization hints would be missing.

This commit adds a RuntimeHints registrar that processes the
`ProblemDetail` type accordingly during the AOT phase.

Fixes gh-29801

spring-web/src/main/java/org/springframework/http/converter/json/ProblemDetailRuntimeHints.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.http.converter.json;
+
+import org.springframework.aot.hint.BindingReflectionHintsRegistrar;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.http.ProblemDetail;
+
+/**
+ * {@link RuntimeHintsRegistrar} implementation that registers binding reflection entries
+ * for {@link ProblemDetail} serialization support with Jackson.
+ *
+ * @author Brian Clozel
+ * @since 6.0.5
+ */
+class ProblemDetailRuntimeHints implements RuntimeHintsRegistrar {
+
+	@Override
+	public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
+		BindingReflectionHintsRegistrar bindingRegistrar = new BindingReflectionHintsRegistrar();
+		bindingRegistrar.registerReflectionHints(hints.reflection(), ProblemDetail.class);
+	}
+
+}