database/sql: fix comment grammar

Author: andreimatei

src/database/sql/driver/driver.go

@@ -26,7 +26,7 @@ import (
 //   time.Time
 //
 // If the driver supports cursors, a returned Value may also implement the Rows interface
-// in this package. This is used when, for example, when a user selects a cursor
+// in this package. This is used, for example, when a user selects a cursor
 // such as "select cursor(select * from my_table) from dual". If the Rows
 // from the select is closed, the cursor Rows will also be closed.
 type Value interface{}