patch 8.1.1254: mapping completion contains dead code

Problem:    Mapping completion contains dead code.
Solution:   Remove the code.
diff --git a/src/version.c b/src/version.c
index c166346..0882fa2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1254,
+/**/
     1253,
 /**/
     1252,