patch 8.2.0592: MS-Windows with VTP: cursor is not made invisible

Problem:    MS-Windows with VTP: cursor is not made invisible.
Solution:   Output the code to make the cursor visible or invisible. (Nobuhiro
            Takasaki, closes #5941)
diff --git a/src/os_win32.c b/src/os_win32.c
index b3e7061..143dab9 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -5996,6 +5996,10 @@
 cursor_visible(BOOL fVisible)
 {
     s_cursor_visible = fVisible;
+
+    if (USE_VTP)
+	vtp_printf("\033[?25%c", fVisible ? 'h' : 'l');
+
 # ifdef MCH_CURSOR_SHAPE
     mch_update_cursor();
 # endif