Update createException example for WebClient

Closes gh-27645

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

@@ -530,7 +530,7 @@ public interface WebClient {
 		 *             return response.bodyToMono(ErrorContainer.class);
 		 *         }
 		 *         else {
-		 *             return Mono.error(response.createException());
+		 *             return response.createException();
 		 *         }
 		 *     });
 		 * </pre>
@@ -562,7 +562,7 @@ public interface WebClient {
 		 *             return response.bodyToMono(ErrorContainer.class).flux();
 		 *         }
 		 *         else {
-		 *             return Flux.error(response.createException());
+		 *             return response.createException().flux();
 		 *         }
 		 *     });
 		 * </pre>

src/docs/asciidoc/web/webflux-webclient.adoc

@@ -559,7 +559,7 @@ depending on the response status:
 				}
 				else {
 					// Turn to error
-					return response.createException().flatMap(Mono::error);
+					return response.createException();
 				}
 			});
 ----