patch 8.2.4285: Vim9: type of item in for loop not checked properly

Problem:    Vim9: type of item in for loop not checked properly.
Solution:   Adjust the type checking. (closes #9683)
diff --git a/src/proto/vim9compile.pro b/src/proto/vim9compile.pro
index cb95fdf..b7f7539 100644
--- a/src/proto/vim9compile.pro
+++ b/src/proto/vim9compile.pro
@@ -4,6 +4,7 @@
 int script_is_vim9(void);
 int script_var_exists(char_u *name, size_t len, cctx_T *cctx);
 int check_defined(char_u *p, size_t len, cctx_T *cctx, int is_arg);
+int need_type_where(type_T *actual, type_T *expected, int offset, where_T where, cctx_T *cctx, int silent, int actual_is_const);
 int need_type(type_T *actual, type_T *expected, int offset, int arg_idx, cctx_T *cctx, int silent, int actual_is_const);
 lvar_T *reserve_local(cctx_T *cctx, char_u *name, size_t len, int isConst, type_T *type);
 int get_script_item_idx(int sid, char_u *name, int check_writable, cctx_T *cctx);