patch 8.2.4418: crash when using special multi-byte character

Problem:    Crash when using special multi-byte character.
Solution:   Don't use isalpha() for an arbitrary character.
diff --git a/src/version.c b/src/version.c
index f95b395..5cb7218 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4418,
+/**/
     4417,
 /**/
     4416,