Changes to special property translations

Heiya Jaider,

this is to make you aware of breaking changes to translations:

[1] https://gerrit.wikimedia.org/r/#/c/135671/1/i18n/pt-br.json

[2] https://gerrit.wikimedia.org/r/#/c/135672/1/i18n/pt-br.json

In the meantime I have already added more information to the message documentation to avoid this, or at least to make it managable for wiki sysadmins.

Cheers