patch 8.1.1681: insert stray "{" when listener gets buffer line

Problem:    Insert stray "{" when listener gets buffer line. (Paul Jolly)
Solution:   Flush the cached line after invoking listeners. (closes #4455)
diff --git a/src/version.c b/src/version.c
index eaa8047..fff8d22 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1681,
+/**/
     1680,
 /**/
     1679,