Added comments on the garbage cleanup logic

amazon-kinesis-client/src/main/java/software/amazon/kinesis/lifecycle/ShutdownTask.java

@@ -146,6 +146,8 @@ public class ShutdownTask implements ConsumerTask {
                                 // in the case of RNF Exception.
                                 attemptShardEndCheckpointing(scope, startTime);
                             } finally {
+                                // If we don't want to cleanup the garbage shard without successful shard end
+                                // checkpointing, remove the try finally construct and only execute the methods.
                                 attemptGarbageCollectionOfLeaseAndEnqueueOnFailure(leasePendingDeletion, currentShardLease);
                             }
                         }