patch 8.1.1832: win_execute() does not work in other tab

Problem:    Win_execute() does not work in other tab. (Rick Howe)
Solution:   Take care of the tab. (closes #4792)
diff --git a/src/proto/window.pro b/src/proto/window.pro
index e9af75b..ccb7a2c 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -90,6 +90,7 @@
 int win_gotoid(typval_T *argvars);
 void win_id2tabwin(typval_T *argvars, list_T *list);
 win_T *win_id2wp(int id);
+win_T *win_id2wp_tp(int id, tabpage_T **tpp);
 int win_id2win(typval_T *argvars);
 void win_findbuf(typval_T *argvars, list_T *list);
 void get_framelayout(frame_T *fr, list_T *l, int outer);