Resolved TODOs in listbox_unix.go; also rewrote some related if expressions there to be clearer.
Resolved TODOs in listbox_unix.go; also rewrote some related if expressions there to be clearer.

ProtonMail/ui,mirrr/ui,robbiev/ui,UIKit0/ui,robbiev/ui,292388900/ui,beni55/ui,janstk/ui,cainiaocome/ui,292388900/ui,hajimehoshi/ui,mirrr/ui,hajimehoshi/ui,beni55/ui,292388900/ui,hajimehoshi/ui,ProtonMail/ui,HunterChen/ui,cainiaocome/ui,janstk/ui,UIKit0/ui,janstk/ui,robbiev/ui,cainiaocome/ui,UIKit0/ui,ProtonMail/ui,HunterChen/ui,HunterChen/ui,mirrr/ui,beni55/ui