patch 8.1.2158: terminal attributes missing in Terminal-normal mode

Problem:    Terminal attributes missing in Terminal-normal mode.
Solution:   Use "syntax_attr".
diff --git a/src/version.c b/src/version.c
index f8602f7..2042cb0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2158,
+/**/
     2157,
 /**/
     2156,