fix:add blank

Author: shmily7829

clients/src/main/java/org/apache/kafka/common/config/TopicConfig.java

@@ -115,7 +115,7 @@ public class TopicConfig {
             "adds entries to its offset index and, conditionally, to its time index. After appending a batch of messages, " +
             "if the total bytes written since the last index entry exceed this value, Kafka will: <br/>" +
             "Add an entry to the offset index for the batch's last offset. <br/>" +
-            "Attempt to add an entry to the time index if the batch's maximum timestamp is greater than the last indexed timestamp. <br/>"+
+            "Attempt to add an entry to the time index if the batch's maximum timestamp is greater than the last indexed timestamp. <br/>" +
             "The default setting ensures that we index a message roughly every 4096 bytes. " +
             "More frequent indexing allows reads to jump closer to the exact position in the log " +
             "but results in larger index files. You probably don't need to change this.";