fix checkstyle

Author: jerry-024

paimon-core/src/test/java/org/apache/paimon/rest/DataTokenProvider.java

@@ -20,8 +20,9 @@
 
 import java.util.Map;
 
-// test for data token refresh.
+/** Test for data token refresh.. */
 public class DataTokenProvider {
+
     private Map<String, String> token;
     private long expiresAtMillis;