patch 8.2.0720: occasional exit when encountering an X error

Problem:    Occasional exit when encountering an X error. (Manfred Lotz)
Solution:   On an X error do not exit, do preserve files.
diff --git a/src/version.c b/src/version.c
index 5903a00..456516f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    720,
+/**/
     719,
 /**/
     718,