patch 9.0.0496: no good reason to keep supporting Windows-XP

Problem:    No good reason to keep supporting Windows-XP.
Solution:   Drop Windows-XP support. (Ken Takata, closes #11089)
diff --git a/runtime/doc/gui_w32.txt b/runtime/doc/gui_w32.txt
index c9e04f3..0cf012b 100644
--- a/runtime/doc/gui_w32.txt
+++ b/runtime/doc/gui_w32.txt
@@ -106,8 +106,7 @@
 You can also install Vim in the "Send To" menu:
 1. Start a Windows Explorer
 2. Navigate to your sendto directory:
-   Windows XP: C:\Documents and Settings\%user%\SendTo
-   Windows Vista: C:\Users\%user%\AppData\Roaming\Microsoft\Windows\SendTo .
+   C:\Users\%user%\AppData\Roaming\Microsoft\Windows\SendTo .
 3. Right-click in the file pane and select New->Shortcut
 4. Follow the shortcut wizard, using the full path to VIM/GVIM.