Fixes regression introduced in ca006f09.

wiki/src/partners.ar.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.ca.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.id.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.pl.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.ru.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.sr_Latn.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.tr.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.zh.po: updating as wiki/src/partners.de.po has changed.
wiki/src/partners.zh_TW.po: updating as wiki/src/partners.de.po has changed.

2019 was our year with more 'pure' partners, both in number of partners
and amount of donations.

The release is tomorrow, most translations for the leaflets are ready,
and I want to avoid translators doing more changes here while I have a
branch ready with a different path for both pages.

Currently translated at 91.7% (44 of 48 strings)

Translation: Tails/wiki/src/about/staging/home.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcaboutstaginghomepo/es/

Currently translated at 91.1% (82 of 90 strings)

Translation: Tails/wiki/src/about/staging/about.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcaboutstagingaboutpo/es/

Currently translated at 82.4% (14 of 17 strings)

Currently translated at 100.0% (9 of 9 strings)

wiki/src/contribute.ar.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.ca.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.id.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.pl.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.ru.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.sr_Latn.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.tr.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.zh.po: updating as wiki/src/contribute.de.po has changed.
wiki/src/contribute.zh_TW.po: updating as wiki/src/contribute.de.po has changed.

Currently translated at 100.0% (9 of 9 strings)

Currently translated at 100.0% (9 of 9 strings)

Thanks to anonym's feedback on #17610, I understood that this mapping
is not obvious, and misunderstandings create confusion, uncertainty,
and make folks do useless extra work.

So let's document better what information one should be looking for *where*,
instead of listing the info we're looking for separately from the sources
of info.