lfb-event: Clarify return values of `finished` functions

They just inidicate that we talked to feedbackd succesfully.

libfeedback/lfb-event.c

@@ -500,7 +500,7 @@ lfb_event_trigger_feedback_async (LfbEvent            *self,
  * must call this function in the callback to free memory and receive any
  * errors which occurred.
  *
- * Returns: %TRUE if playing finished successfully
+ * Returns: %TRUE if triggering the feedbacks was successful
  */
 gboolean
 lfb_event_trigger_feedback_finish (LfbEvent      *self,
@@ -552,7 +552,10 @@ lfb_event_end_feedback (LfbEvent *self, GError **error)
  * must call this function in the callback to free memory and receive any
  * errors which occurred.
  *
- * Returns: %TRUE if playing finished successfully
+ * This does not mean that the feedbacks finished right away. Connect to the
+ * #LfbEvent::feedback-ended signal for this.
+ *
+ * Returns: %TRUE if ending the feedbacks was successful
  */
 gboolean
 lfb_event_end_feedback_finish (LfbEvent      *self,