patch 8.1.1905: cannot set all properties of the info popup

Problem:    Cannot set all properties of the info popup.
Solution:   Add popup_findinfo().  Rename popup_getpreview() to
            popup_findpreview().
diff --git a/src/proto/popupwin.pro b/src/proto/popupwin.pro
index 9f6d433..0507114 100644
--- a/src/proto/popupwin.pro
+++ b/src/proto/popupwin.pro
@@ -27,6 +27,7 @@
 void f_popup_notification(typval_T *argvars, typval_T *rettv);
 void f_popup_close(typval_T *argvars, typval_T *rettv);
 void f_popup_hide(typval_T *argvars, typval_T *rettv);
+void popup_show(win_T *wp);
 void f_popup_show(typval_T *argvars, typval_T *rettv);
 void f_popup_settext(typval_T *argvars, typval_T *rettv);
 void popup_close(int id);
@@ -49,9 +50,11 @@
 win_T *popup_find_preview_window(void);
 int popup_is_popup(win_T *wp);
 win_T *popup_find_info_window(void);
-void f_popup_getpreview(typval_T *argvars, typval_T *rettv);
+void f_popup_findinfo(typval_T *argvars, typval_T *rettv);
+void f_popup_findpreview(typval_T *argvars, typval_T *rettv);
 int popup_create_preview_window(int info);
-void popup_close_preview(int info);
+void popup_close_preview(void);
+void popup_hide_info(void);
 void popup_set_title(win_T *wp);
 void popup_update_preview_title(void);
 /* vim: set ft=c : */