deskutils/fet: update to 6.3.4

ChangeLog: https://www.lalescu.ro/liviu/fet/news.html

• Minor improvements.
• Minor correction in the Arabic translation, by Benahmed Abdelkrim.
• Updated the Russian translation, by Alexey Chernous.

PR: 263937
Reported by: uzsolt@uzsolt.hu (maintainer)