bug#44597: 26.3; bibtex should allow reverse sorting

[Roland Winkler]

On Mon Dec 7 2020 Francesco Potortì wrote:
> Ah, I forgot.
> 
> I did not include it in the patch, but I think that
> bibtex-autokey-get-field should be renamed to bibtex-get-field

I'll look into this patch.

(I believe bibtex-autokey-get-field need not be renamed.
But it will be better to call instead the low-level function
bibtex-text-in-field.)