CLEANUP: stream-int: fix a few outdated comments about stream_int_register_handler()

They were not updated after the infrastructure change.
diff --git a/src/stream_interface.c b/src/stream_interface.c
index 7e201cd..97add68 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -375,13 +375,11 @@
 		task_wakeup(si_task(si), TASK_WOKEN_IO);
 }
 
-/* Register an applet to handle a stream_interface as part of the
- * stream interface's owner task. The SI will wake it up everytime it
- * is solicited.  The task's processing function must call the applet's
- * function before returning. It must be deleted by the task handler
- * using stream_int_unregister_handler(), possibly from within the
- * function itself. It also pre-initializes the applet's context and
- * returns it (or NULL in case it could not be allocated).
+/* Register an applet to handle a stream_interface as a new appctx. The SI will
+ * wake it up everytime it is solicited. The appctx must be deleted by the task
+ * handler using si_release_endpoint(), possibly from within the function itself.
+ * It also pre-initializes the applet's context and returns it (or NULL in case
+ * it could not be allocated).
  */
 struct appctx *stream_int_register_handler(struct stream_interface *si, struct applet *app)
 {