HADOOP-16602. mvn package fails in hadoop-aws.

Contributed by Xieming Li.

Follow-up to HADOOP-16445

Change-Id: I72c62d55b734a0f67556844f398ef4a50d9ea585

Author: risyomei

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/Constants.java

@@ -353,8 +353,8 @@ private Constants() {
   /**
    * List of custom Signers. The signer class will be loaded, and the signer
    * name will be associated with this signer class in the S3 SDK. e.g. Single
-   * CustomSigner -> 'CustomSigner:org.apache...CustomSignerClass Multiple
-   * CustomSigners -> 'CSigner1:CustomSignerClass1,CSigner2:CustomerSignerClass2
+   * CustomSigner {@literal ->} 'CustomSigner:org.apache...CustomSignerClass Multiple
+   * CustomSigners {@literal ->} 'CSigner1:CustomSignerClass1,CSigner2:CustomerSignerClass2
    */
   public static final String CUSTOM_SIGNERS = "fs.s3a.custom.signers";