doc: describe kinesis flattening

Author: Devdutt Shenoi

src/handlers/http/modal/utils/ingest_utils.rs

@@ -49,6 +49,7 @@ pub async fn flatten_and_push_logs(
 ) -> Result<(), PostError> {
     match log_source {
         LogSource::Kinesis => {
+            //custom flattening required for Amazon Kinesis
             let message: Message = serde_json::from_value(json)?;
             for record in flatten_kinesis_logs(message) {
                 push_logs(stream_name, record, &LogSource::default()).await?;