t/languages.t documentlanguage test failure

[Gavin Smith]

The test "perl -w t/languages.t documentlanguage" started failing
recently for me.  This test refers to the input file
tp/tests/formatting/documentlanguage.texi which specifies
"@documentlanguage pt".

The results for this test were updated recently
(commit 6c70eec56d90, Patrice Dumas <pertu...@free.fr>  2023-10-29);
however, I still get the old results.  Diff at the end of this mail.

The difference appears to be whether pt or pt_BR translations are used.
I am getting the Brazillian Portuguese (pt_BR) results with Próximo,
while the reference test results use Seguinte (pt).

Neither pt.po or pt_BR.po appear to have been updated recently so I am
not sure why the test results would have changed?

pt_BR.po has "PO-Revision-Date: 2021-06-16 11:08-0300\n" and
pt.po has "PO-Revision-Date: 2021-06-17 06:32+0100\n".

I guess it is correct for pt.po to be used for "@documentlanguage pt" --
any idea why this is not happening on my system while it was when the
test results were recently updated?  Has anything changed about how
translations are retrieved?

FWIW I get the same results both with TEXINFO_XS=require and with
TEXINFO_XS=omit.



diff t/results/languages/documentlanguage/res_html/documentlanguage.html 
t/results/languages/documentlanguage/out_html/documentlanguage.html
39c39
< Seguinte: <a href="#chapter" accesskey="n" rel="next">Chapter</a> &nbsp; [<a 
href="#chapter" title="Índice" rel="index">Índice</a>]</p>
---
> Pr&oacute;ximo: <a href="#chapter" accesskey="n" rel="next">Chapter</a> 
> &nbsp; [<a href="#chapter" title="&Iacute;ndice" 
> rel="index">&Iacute;ndice</a>]</p>
50c50
< Anterior: <a href="#Top" accesskey="p" rel="prev">top section</a>, Acima: <a 
href="#Top" accesskey="u" rel="up">top section</a> &nbsp; [<a href="#chapter" 
title="Índice" rel="index">Índice</a>]</p>
---
> Nodo anterior: <a href="#Top" accesskey="p" rel="prev">top section</a>, 
> Acima: <a href="#Top" accesskey="u" rel="up">top section</a> &nbsp; [<a 
> href="#chapter" title="&Iacute;ndice" rel="index">&Iacute;ndice</a>]</p>
63c63
< <tr><td></td><th class="entries-header-printindex">Entrada de índice</th><th 
class="sections-header-printindex">Secção</th></tr>
---
> <tr><td></td><th class="entries-header-printindex">Entrada de 
> &Iacute;ndice</th><th 
> class="sections-header-printindex">Se&ccedil;&atilde;o</th></tr>