miniterm: doc update for win32 cancel
diff --git a/serial/tools/miniterm.py b/serial/tools/miniterm.py
index 7b4e3af..420bf12 100644
--- a/serial/tools/miniterm.py
+++ b/serial/tools/miniterm.py
@@ -127,7 +127,8 @@
                     return z
 
         def cancel(self):
-            # XXX check if CancelIOEx could be used
+            # CancelIo, CancelSynchronousIo do not seem to work when using
+            # getwch, so instead, send a key to the window with the console
             hwnd = ctypes.windll.kernel32.GetConsoleWindow()
             ctypes.windll.user32.PostMessageA(hwnd, 0x100, 0x0d, 0)