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

[Stefan Monnier]

> (defsubst file-attribute-file-number (attributes)
>   "The inode and device numbers in ATTRIBUTES returned by `file-attributes'.
> It can be used to determine whether two files are identical."
>   (nthcdr 10 attributes))
>
> WDYT?

Sounds good, except:

- The name `file-attribute-file-number` doesn't sound right
  because it doesn't return a number.

- I wouldn't use `defsubst` (so it can more easily be modified in the
  future, e.g. in case we add more fields to the attributes or use some
  other representation for attributes).

- I would document it more abstractly, mentioning inode and device
  number only as *examples* of things it might contain.


        Stefan