various doc fixes

sql/core/src/main/java/org/apache/spark/sql/sources/v2/writer/DataWriter.java

@@ -38,7 +38,7 @@
  * succeeds), a {@link WriterCommitMessage} will be sent to the driver side and pass to
  * {@link DataSourceWriter#commit(WriterCommitMessage[])} with commit messages from other data
  * writers. If this data writer fails(one record fails to write or {@link #commit()} fails), an
- * exception will be sent to the driver side, and Spark will retry this writing task for some times,
+ * exception will be sent to the driver side, and Spark may retry this writing task for some times,
  * each time {@link DataWriterFactory#createDataWriter(int, int, long)} gets a different
  * `attemptNumber`, and finally call {@link DataSourceWriter#abort(WriterCommitMessage[])} if all
  * retry fail.

sql/core/src/main/java/org/apache/spark/sql/sources/v2/writer/DataWriterFactory.java

@@ -49,8 +49,8 @@ public interface DataWriterFactory<T> extends Serializable {
    *                      tasks with the same task id running at the same time. Implementations can
    *                      use this attempt number to distinguish writers of different task attempts.
    * @param epochId A monotonically increasing id for streaming queries that are split in to
-   *                discrete periods of execution. For queries that execute as a single batch, this
-   *                id will always be zero.
+   *                discrete periods of execution. For non-streaming queries,
+   *                this ID will always be 0.
    */
   DataWriter<T> createDataWriter(int partitionId, int attemptNumber, long epochId);
 }