patch 8.1.0840: getchar(0) never returns a character in the terminal

Problem:    getchar(0) never returns a character in the terminal.
Solution:   Call wait_func() at least once.
diff --git a/src/version.c b/src/version.c
index b69344c..ae28d08 100644
--- a/src/version.c
+++ b/src/version.c
@@ -784,6 +784,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    840,
+/**/
     839,
 /**/
     838,