cal package russian translation

[dv <udv.mysql@gmail.com>]

Hello.

Debian stretch/buster have very strange translation of month's names
in Russian language.
"cal" package in Russian translation uses Genitive case instead of
Nominative case, and gives very strange result.
Января...Декабря instead of Январь...Декабрь.
Please make correction of translation.
Thank you very much.

Best regards, Dmitry.