Merge pull request #15733 from NaitYoussef

* pr/15733:
  Polish contribution
  Fix typo

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/context/runner/AbstractApplicationContextRunner.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -38,7 +38,7 @@ import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.util.Assert;
 
 /**
- * Utility design to run and an {@link ApplicationContext} and provide AssertJ style
+ * Utility design to run an {@link ApplicationContext} and provide AssertJ style
  * assertions. The test is best used as a field of a test class, describing the shared
  * configuration required for the test:
  *