patch 8.1.2181: highlighting wrong when item follows tab

Problem:    Highlighting wrong when item follows tab.
Solution:   Don't use syntax attribute when n_extra is non-zero.
            (Christian Brabandt, closes #5076)
diff --git a/src/version.c b/src/version.c
index aebadab..0fff97d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2181,
+/**/
     2180,
 /**/
     2179,