bug#51456: website: Language selection dropdown not translated

["pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de>]

Ludo recently divided building the website into one computed file for
each language (“lingua”) in order to offload the build (a good thing;
thank you Ludo).

However, this includes making available for each lingua only the
translations MO file for that lingua.

Specifically .guix.scm now links only that file:

(symlink (string-append #$(lingua-mo-files lingua) "/" lingua)
         lingua)

But on the website, there is a language selection dropdown at the top
right and the names of alternative language are taken from that
language’s MO file.

Because the build does not have available all MO files anymore, all
foreign languages are now called English.

(Another effect is that the contact web page only lists the German
message for the Help mailing list on the German website but meh …)

Is the proper solution to symlink all lingua-mo-files, i.e. reinstate
from before commit 4d5bf8522e2 a for-each like

(for-each
 (lambda (lingua mo-directory)
         (symlink (string-append mo-directory "/" lingua)
                  lingua))
 (list #$@%linguas)
 '#$(map lingua-mo-files %linguas))

(I have not tried.)

Or should website/apps/base/templates/components.scm look up the
language dropdown’s language names in a different way such as from the
PO file, which is more complicated?

Regards,
Florian