patch 8.1.2159: some mappings are listed twice

Problem:    Some mappings are listed twice.
Solution:   Skip mappings duplicated for modifyOtherKeys. (closes #5064)
diff --git a/src/version.c b/src/version.c
index 2042cb0..91cffb3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2159,
+/**/
     2158,
 /**/
     2157,