patch 8.1.1640: the CursorHold autocommand takes down a balloon

Problem:    The CursorHold autocommand takes down a balloon. (Paul Jolly)
Solution:   Ignore the CursorHold pseudo-key.
diff --git a/src/version.c b/src/version.c
index 25c6076..85cf7b2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1640,
+/**/
     1639,
 /**/
     1638,