patch 8.2.3788: lambda for option that is a function may be freed

Problem:    Lambda for option that is a function may be garbage collected.
Solution:   Set a reference in the funcref. (Yegappan Lakshmanan,
            closes #9330)
diff --git a/src/proto/ops.pro b/src/proto/ops.pro
index c46af05..1e89c4e 100644
--- a/src/proto/ops.pro
+++ b/src/proto/ops.pro
@@ -19,5 +19,6 @@
 void cursor_pos_info(dict_T *dict);
 int set_operatorfunc_option(void);
 void free_operatorfunc_option(void);
+int set_ref_in_opfunc(int copyID);
 void do_pending_operator(cmdarg_T *cap, int old_col, int gui_yank);
 /* vim: set ft=c : */