patch 9.0.0423: "for" and "while" not recognized after :vim9cmd and :legacy

Problem:    "for" and "while" not recognized after :vim9cmd and :legacy.
            (Emanuele Torre)
Solution:   Recognize all the command modifiers. (closes #11087)
            Add a test to check the list of modifiers.
diff --git a/src/version.c b/src/version.c
index fe87dab..445ac6d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -704,6 +704,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    423,
+/**/
     422,
 /**/
     421,