patch 8.2.1399: Vim9: may find imported item in wrong script

Problem:    Vim9: may find imported item in wrong script.
Solution:   When looking up script-local function use the embedded script ID.
            (issue #6644)
diff --git a/src/proto/vim9compile.pro b/src/proto/vim9compile.pro
index 14f9bbc..2de542b 100644
--- a/src/proto/vim9compile.pro
+++ b/src/proto/vim9compile.pro
@@ -12,6 +12,7 @@
 char *type_name(type_T *type, char **tofree);
 int get_script_item_idx(int sid, char_u *name, int check_writable);
 imported_T *find_imported(char_u *name, size_t len, cctx_T *cctx);
+imported_T *find_imported_in_script(char_u *name, size_t len, int sid);
 int vim9_comment_start(char_u *p);
 char_u *peek_next_line_from_context(cctx_T *cctx);
 char_u *next_line_from_context(cctx_T *cctx, int skip_comment);