patch 9.0.0283: cannot complete "syn list @cluster"

Problem:    Cannot complete "syn list @cluster".
Solution:   Recognize and handle "list @". (Björn Linse, closes #10990)
diff --git a/src/version.c b/src/version.c
index 2eb817c..c3fbe5f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -708,6 +708,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    283,
+/**/
     282,
 /**/
     281,