Upgrade to Checkstyle 9.0 and spring-javaformat 0.0.29

This commit upgrades the Gradle build to use Checkstyle 9.0 and
spring-javaformat 0.0.29 (which internally uses Checkstyle 8.45.1).

Closes gh-27520

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/WebClient.java

@@ -469,10 +469,10 @@ public interface WebClient {
 		/**
 		 * Provide a function to populate the Reactor {@code Context}.
 		 * @param contextModifier the function to modify the context with
+		 * @since 5.3.1
 		 * @deprecated in 5.3.2 to be removed soon after; this method cannot
 		 * provide context to downstream (nested or subsequent) requests and is
 		 * of limited value.
-		 * @since 5.3.1
 		 */
 		@Deprecated
 		S context(Function<Context, Context> contextModifier);