MINOR: Fix ConsumerConfig.ISOLATION_LEVEL_DOC (#11915)

Reviewers: David Jacot <djacot@confluent.io>

clients/src/main/java/org/apache/kafka/clients/consumer/ConsumerConfig.java

@@ -312,7 +312,7 @@ public class ConsumerConfig extends AbstractConfig {
             " <code>read_committed</code> mode, consumer.poll() will only return messages up to the last stable offset (LSO), which is the one less than the offset of the first open transaction." +
             " In particular any messages appearing after messages belonging to ongoing transactions will be withheld until the relevant transaction has been completed. As a result, <code>read_committed</code>" +
             " consumers will not be able to read up to the high watermark when there are in flight transactions.</p><p> Further, when in <code>read_committed</code> the seekToEnd method will" +
-            " return the LSO";
+            " return the LSO</p>";
 
     public static final String DEFAULT_ISOLATION_LEVEL = IsolationLevel.READ_UNCOMMITTED.toString().toLowerCase(Locale.ROOT);