patch 8.2.4397: crash when using many composing characters in error message

Problem:    Crash when using many composing characters in error message.
Solution:   Use mb_cptr2char_adv() instead of mb_ptr2char_adv().
diff --git a/src/version.c b/src/version.c
index fb1b847..b498366 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4397,
+/**/
     4396,
 /**/
     4395,