Correct reference to Offset class

This is a documentation-only correction; `org.apache.spark.sql.sources.v2.reader.Offset` is actually `org.apache.spark.sql.sources.v2.reader.streaming.Offset`.

Author: Seth Fitzsimmons <[email protected]>

Closes #21387 from mojodna/patch-1.

Author: mojodna

sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/Offset.java

@@ -19,8 +19,8 @@
 
 /**
  * This is an internal, deprecated interface. New source implementations should use the
- * org.apache.spark.sql.sources.v2.reader.Offset class, which is the one that will be supported
- * in the long term.
+ * org.apache.spark.sql.sources.v2.reader.streaming.Offset class, which is the one that will be
+ * supported in the long term.
  *
  * This class will be removed in a future release.
  */