Merge branch '2.3.x' into 2.4.x

Closes gh-26324

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/NamedContributors.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -33,7 +33,7 @@ public interface NamedContributors<C> extends Iterable<NamedContributor<C>> {
 	/**
 	 * Return the contributor with the given name.
 	 * @param name the name of the contributor
-	 * @return a contributor instance of {@code null}
+	 * @return a contributor instance or {@code null}
 	 */
 	C getContributor(String name);