fix(messages): add "list_cmd" kind to :colorscheme #37561

Problem:  No kind for :colorscheme message.
Solution: Assign it the "list_cmd" kind.

src/nvim/ex_docmd.c

@@ -4758,6 +4758,7 @@ static void ex_colorscheme(exarg_T *eap)
     emsg_off--;
     xfree(expr);
 
+    msg_ext_set_kind("list_cmd");
     if (p != NULL) {
       msg(p, 0);
       xfree(p);