patch 8.1.0016: possible crash in term_wait()

Problem:    Possible crash in term_wait(). (Dominique Pelle)
Solution:   Check for a valid buffer after ui_delay(). (closes #2944)
diff --git a/src/version.c b/src/version.c
index d1a75a1..7d941bb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    16,
+/**/
     15,
 /**/
     14,