patch 9.0.0659: wrong type of comment in SetSyn() function

Problem:    Wrong type of comment in SetSyn() function.
Solution:   Use Vim9 comment. (closes #11278)
diff --git a/src/version.c b/src/version.c
index caaf968..ce0dce0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    659,
+/**/
     658,
 /**/
     657,