patch 8.1.1278: missing change for "combine" field

Problem:    Missing change for "combine" field.
Solution:   Also change the textprop implementation.
diff --git a/src/version.c b/src/version.c
index 7930e3c..0b47695 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1278,
+/**/
     1277,
 /**/
     1276,