[PHP-DOC] Switching RU translation on

[Alexey Shein]

Hello, guys!
Could you please enable RU translation on the official mirrors?
Our team made amazing work: translated part reached 27% (4th place
after French, Japanese and Spanish) and stale files are less than 1%.
It seems the time has come :)
Thanks.
-- 
Regards,
Shein Alexey