patch 9.0.0641: missing part of the new option code

Problem:    Missing part of the new option code.
Solution:   Add missing WV_SMS.
diff --git a/src/option.h b/src/option.h
index 97b7a6c..3e6f2cb 100644
--- a/src/option.h
+++ b/src/option.h
@@ -1276,6 +1276,7 @@
 #endif
     , WV_SCBIND
     , WV_SCROLL
+    , WV_SMS
     , WV_SISO
     , WV_SO
 #ifdef FEAT_SPELL