patch 9.1.0984: exception handling can be improved

Problem:  exception handling can be improved
Solution: add v:stacktrace and getstacktrace()

closes: #16360

Co-authored-by: Naruhiko Nishino <naru123456789@gmail.com>
Signed-off-by: ichizok <gclient.gaap@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/scriptfile.pro b/src/proto/scriptfile.pro
index c8ff04a..e81d16b 100644
--- a/src/proto/scriptfile.pro
+++ b/src/proto/scriptfile.pro
@@ -5,6 +5,8 @@
 int estack_top_is_ufunc(ufunc_T *ufunc, long lnum);
 estack_T *estack_pop(void);
 char_u *estack_sfile(estack_arg_T which);
+list_T *stacktrace_create(void);
+void f_getstacktrace(typval_T *argvars, typval_T *rettv);
 void ex_runtime(exarg_T *eap);
 void set_context_in_runtime_cmd(expand_T *xp, char_u *arg);
 int find_script_by_name(char_u *name);