Use "release notes" in message as it is more generic

Author: snicoll

spring-boot-project/spring-boot-properties-migrator/src/main/java/org/springframework/boot/context/properties/migrator/PropertiesMigrationReport.java

@@ -71,7 +71,7 @@ String getErrorReport() {
 				"%nThe use of configuration keys that are no longer supported was found in the environment:%n%n"));
 		append(report, content);
 		report.append(String.format("%n"));
-		report.append("Please refer to the migration guide or reference guide for potential alternatives.");
+		report.append("Please refer to the release notes or reference guide for potential alternatives.");
 		report.append(String.format("%n"));
 		return report.toString();
 	}

spring-boot-project/spring-boot-properties-migrator/src/test/java/org/springframework/boot/context/properties/migrator/PropertiesMigrationListenerTests.java

@@ -50,7 +50,7 @@ void sampleReport(CapturedOutput output) {
 		this.context = createSampleApplication().run("--logging.file=test.log");
 		assertThat(output).contains("commandLineArgs").contains("logging.file.name")
 				.contains("Each configuration key has been temporarily mapped")
-				.doesNotContain("Please refer to the migration guide");
+				.doesNotContain("Please refer to the release notes");
 	}
 
 	private SpringApplication createSampleApplication() {