bug#58446: 28.2; file-attribute-device-number returns a cons cell instead of an integer

[Thierry Volpiatto]

The device-number in file-attributes (nth 11) is a cons cell when called
on remote files (see tramp-get-device).
It would be great to notify this in Emacs documentation and how to
interpret this value e.g. (-1 . 1).
I noticed this in fixing a bug in dired-async.el, the code was using `=`
to compare the two values which is legitimate according to docstring.


In GNU Emacs 28.2 (build 1, x86_64-pc-linux-gnu, Motif Version 2.3.8, cairo 
version 1.16.0)
 of 2022-09-12 built on IPad-S340
Windowing system distributor 'The X.Org Foundation', version 11.0.12013000
System Description: Linux Mint 20.3

Configured using:
 'configure CFLAGS=-O8 --with-mailutils --with-cairo --without-dbus
 --without-gconf --without-gsettings --with-x-toolkit=motif'

Configured features:
ACL CAIRO FREETYPE GIF GLIB GMP GNUTLS GPM HARFBUZZ JPEG JSON LCMS2
LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY
PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE
XIM XPM MOTIF ZLIB

Important settings:
  value of $LANG: fr_FR.UTF-8
  locale-coding-system: utf-8-unix

Major mode: ƐĽ

Minor modes in effect:
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Load-path shadows:
None found.

Features:
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Memory information:
((conses 16 1834152 77310)
 (symbols 48 43794 4)
 (strings 32 346905 22367)
 (string-bytes 1 12371838)
 (vectors 16 89769)
 (vector-slots 8 1894146 124249)
 (floats 8 3996 656)
 (intervals 56 347767 1990)
 (buffers 992 115))
<#secure method=pgpmime mode=sign>

-- 
Thierry