I18n: Update translation fr (100%).

74 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation pl (100%).

74 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation zh_TW (100%).

74 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).