Document that the output file is not deleted in case of error/cancel

PiperOrigin-RevId: 511189130

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/Transformer.java

@@ -490,6 +490,8 @@ public final class Transformer {
     /**
      * Called if an exception occurs during the export.
      *
+     * <p>The export output file (if any) is not deleted in this case.
+     *
      * @param composition The {@link Composition} for which the exception occurs.
      * @param exportResult The {@link ExportResult} of the export.
      * @param exportException The {@link ExportException} describing the exception. This is the same
@@ -852,6 +854,8 @@ public final class Transformer {
   /**
    * Cancels the export that is currently in progress, if any.
    *
+   * <p>The export output file (if any) is not deleted.
+   *
    * @throws IllegalStateException If this method is called from the wrong thread.
    */
   public void cancel() {