Update yii.php

Without word "Atrybut" (english "attribute") this phrase is grammatically incorrect when noun representing field name isn't masculine (e.g. "Hasło musi być powtórzony" should be "Hasło musi być powtórzone". "Hasło" means english "Password"). 
Also, I added missing word "exactly" (polish "dokładnie") and removed word "ponownie" (this is pleonasm http://en.wikipedia.org/wiki/Pleonasm)