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/os_win32.txt b/runtime/doc/os_win32.txt
index 0eb065f..10dcdf4 100644
--- a/runtime/doc/os_win32.txt
+++ b/runtime/doc/os_win32.txt
@@ -7,8 +7,11 @@
 						*win32* *Win32* *MS-Windows*
 This file documents the idiosyncrasies of the Win32 version of Vim.
 
-The Win32 version of Vim works on Windows XP, Vista, 7, 8, 10 and 11.  There are
-both console and GUI versions.
+The Win32 version of Vim works on Windows 7, 8, 10 and 11.  There are both
+console and GUI versions.
+
+If you have Windows XP or Vista then Vim 9.0 up to patch level 495 can be
+used.
 
 The 32 bit version also runs on 64 bit MS-Windows systems.