fix comments

Author: uncleGen

external/kafka-0-10-sql/src/test/scala/org/apache/spark/sql/kafka010/KafkaContinuousSourceSuite.scala

@@ -170,7 +170,7 @@ class KafkaContinuousSourceSuite extends KafkaSourceSuiteBase with KafkaContinuo
     }
   }
 
-  test(s"SPARK-27494: read kafka record containing null key/values in continuous mode") {
+  test("SPARK-27494: read kafka record containing null key/values in continuous mode") {
     testNullableKeyValue(ContinuousTrigger(100))
   }
 }

external/kafka-0-10-sql/src/test/scala/org/apache/spark/sql/kafka010/KafkaMicroBatchSourceSuite.scala

@@ -1041,7 +1041,7 @@ abstract class KafkaMicroBatchSourceSuiteBase extends KafkaSourceSuiteBase {
     }
   }
 
-  test(s"SPARK-27494: read kafka record containing null key/values in micro-batch mode") {
+  test("SPARK-27494: read kafka record containing null key/values in micro-batch mode") {
     testNullableKeyValue(Trigger.ProcessingTime(100))
   }
 }