Fix some constness and add comments.
Fix some constness and add comments.

daemonl/rofi,stettberger/rofi,jubalh/rofi,jreinert/rofi,stettberger/rofi,ThomasAdam/rofi,daemonl/rofi,t-wissmann/rofi,eigengrau/rofi,carnager/rofi,carnager/rofi,eigengrau/rofi,jubalh/rofi,carnager/rofi,t-wissmann/rofi,ThomasAdam/rofi,jreinert/rofi