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

[Drew Adams]

> >   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.

Yes, that's fine.

(And it's good to say that `w' is a write bit.)


[But do we usually write "MS-Windows" or "MS Windows"?]