patch 9.0.0253: a symlink to an autoload script results in two entries

Problem:    A symlink to an autoload script results in two entries in the list
            of scripts, items expected in one are actually in the other.
Solution:   Have one script item refer to the actually sourced one.
            (closes #10960)
diff --git a/src/proto/vim9script.pro b/src/proto/vim9script.pro
index 04c07fc..0e98039 100644
--- a/src/proto/vim9script.pro
+++ b/src/proto/vim9script.pro
@@ -12,6 +12,7 @@
 void free_imports_and_script_vars(int sid);
 void mark_imports_for_reload(int sid);
 void ex_import(exarg_T *eap);
+void import_check_sourced_sid(int *sid);
 int find_exported(int sid, char_u *name, ufunc_T **ufunc, type_T **type, cctx_T *cctx, cstack_T *cstack, int verbose);
 char_u *vim9_declare_scriptvar(exarg_T *eap, char_u *arg);
 void update_vim9_script_var(int create, dictitem_T *di, char_u *name, int flags, typval_T *tv, type_T **type, int do_member);