Add rofi lecture picker + fix double keybinding

config/rofi/menus/lectures.fish

@@ -0,0 +1,15 @@
+#!/usr/bin/env fish
+
+# User chooses lecture
+set LECTURE (exa -1 -D ~/Notes/TU | rofi -theme ~/NixFlake/config/rofi/rofi.rasi -dmenu -p "lecture" -i)
+if test -z $LECTURE
+    exit
+end
+
+# User chooses slides
+set DECK (exa -1 ~/Notes/TU/$LECTURE/Lecture | grep ".pdf" | rofi -theme ~/NixFlake/config/rofi/rofi.rasi -dmenu -p "deck" -i)
+if test -z $DECK
+    exit
+end
+
+xdg-open ~/Notes/TU/$LECTURE/Lecture/$DECK