bug#24897: 24.5; doc for `M' in Dired

[Eli Zaretskii]

> Date: Fri, 11 Oct 2019 17:51:31 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 24897@debbugs.gnu.org
> 
>   Note that on MS-Windows this command can only set or reset
>   the `w' (write) bit, but cannot change any other bits.

Actually, here's a more useful text:

  Note that on MS-Windows only the `w' (write) bit is meaningful:
  resetting it makes the file read-only.  Changing any other bit
  has no effect on MS-Windows.