patch 8.0.0914: highlight attributes are always combined

Problem:    Highlight attributes are always combined.
Solution:   Add the 'nocombine' value to replace attributes instead of
            combining them. (scauligi, closes #1963)
diff --git a/src/version.c b/src/version.c
index 314b62d..72701c9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    914,
+/**/
     913,
 /**/
     912,