patch 8.2.4744: a terminal window can't use the bell

Problem:    A terminal window can't use the bell.
Solution:   Add bell support for the terminal window. (closes #10178)
diff --git a/src/gui_w32.c b/src/gui_w32.c
index d1cc06d..35cb2d2 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -1696,7 +1696,7 @@
     void
 gui_mch_beep(void)
 {
-    MessageBeep(MB_OK);
+    MessageBeep((UINT)-1);
 }
 /*
  * Invert a rectangle from row r, column c, for nr rows and nc columns.