tweak docs

offset_commit_request.go

@@ -5,8 +5,8 @@ package sarama
 // The timestamp is only used if message version 1 is used, which requires kafka 0.8.2.
 const ReceiveTime int64 = -1
 
-// GroupGenerationUndefined is a special value of group generation field of
-// Offset Commit Request that should be used when a consumer group does not rely
+// GroupGenerationUndefined is a special value for the group generation field of
+// Offset Commit Requests that should be used when a consumer group does not rely
 // on Kafka for partition management.
 const GroupGenerationUndefined = -1