patch 8.2.0729: Vim9: When reloading a script variables are not cleared

Problem:    Vim9: When reloading a script variables are not cleared.
Solution:   When sourcing a script again clear all script-local variables.
diff --git a/src/proto/dict.pro b/src/proto/dict.pro
index d9b35c3..45bcfbf 100644
--- a/src/proto/dict.pro
+++ b/src/proto/dict.pro
@@ -5,6 +5,7 @@
 int rettv_dict_alloc(typval_T *rettv);
 void rettv_dict_set(typval_T *rettv, dict_T *d);
 void dict_free_contents(dict_T *d);
+void hashtab_free_contents(hashtab_T *ht);
 void dict_unref(dict_T *d);
 int dict_free_nonref(int copyID);
 void dict_free_items(int copyID);