Bug#791506: [www.debian.org] Content negotiation doesn't work properly with pt_BR at the Release Notes web page

Package: www.debian.org
Followup-For: Bug #791506
Control: retitle -1 [www.debian.org] Release notes are translated per-language, not per-locale

> Content negotiation works well: if you have pt-BR and pt locales enabled in
> browser, and go to https://www.debian.org/releases/bullseye/releasenotes you
> are presented a "pt" translation of the page (because there is no pt-br
> translation of that page) and thus the links to "Português" are in bold
> instead of the links to "Português (Brasileiro)".

Ah, OK: that makes sense, thank you.  I agree that content negotiation is
working as expected (and have retitled the bug).

> So (correct me if I'm wrong) I think the best is leave things as they are,
> suggest users to include both pt-br and pt locales in their browser, and
> close this bug. 

That sounds correct.  Before we do that, there is one idea/workaround I had
that probably has flaws, but that I would like to mention:

We could update the logic here to use lang.startswith instead of lang.equals:

  - https://salsa.debian.org/webmaster-team/webwml/-/blob/master/english/template/debian/release.wml#L216-218

That would mean that when content-negotiation finds the most-relevant available
translation for a page (say, 'pt'), we embolden all of the potential
translations.

(I think it would remain as-cacheable as today, and that any resulting bundling
of the release notes HTML into redistributable packages should not increase in
variance as a result of it)