patch 9.0.0024: may access part of typeahead buf that isn't filled

Problem:    May access part of typeahead buf that isn't filled.
Solution:   Check length of typeahead.
diff --git a/src/version.c b/src/version.c
index fe683f4..e8d506c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -736,6 +736,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    24,
+/**/
     23,
 /**/
     22,