Adjust ClusterAdmin godoc comments

admin.go

@@ -20,7 +20,7 @@ type ClusterAdmin interface {
 	// List the topics available in the cluster with the default options.
 	ListTopics() (map[string]TopicDetail, error)
 
-	// Describe some topics in the cluster
+	// Describe some topics in the cluster.
 	DescribeTopics(topics []string) (metadata []*TopicMetadata, err error)
 
 	// Delete a topic. It may take several seconds after the DeleteTopic to returns success
@@ -78,13 +78,13 @@ type ClusterAdmin interface {
 	// List the consumer groups available in the cluster.
 	ListConsumerGroups() (map[string]string, error)
 
-	// Describe the given consumer group
+	// Describe the given consumer groups.
 	DescribeConsumerGroups(groups []string) ([]*GroupDescription, error)
 
 	// List the consumer group offsets available in the cluster.
 	ListConsumerGroupOffsets(group string, topicPartitions map[string][]int32) (*OffsetFetchResponse, error)
 
-	// Get information about the nodes in the cluster
+	// Get information about the nodes in the cluster.
 	DescribeCluster() (brokers []*Broker, controllerID int32, err error)
 
 	// Close shuts down the admin and closes underlying client.