patch 8.0.1231: expanding file name drops dash

Problem:    Expanding file name drops dash. (stucki)
Solution:   Use the right position. (Christian Brabandt, closes #2184)
diff --git a/src/version.c b/src/version.c
index 221c757..4ce6fee 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1231,
+/**/
     1230,
 /**/
     1229,