patch 8.2.0476: terminal nasty callback test fails sometimes

Problem:    Terminal nasty callback test fails sometimes.
Solution:   use term_wait() instead of a sleep. (Yee Cheng Chin,closes #5865)
diff --git a/src/version.c b/src/version.c
index 69afadf..73de61c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    476,
+/**/
     475,
 /**/
     474,