removed unecessary functions

ansible/roles/fish/files/fish/functions/decrease_brightness_by.fish

@@ -1,5 +0,0 @@
-function decrease_brightness_by --argument-names amount
-  set --local brightness (cat /sys/class/backlight/*/brightness)
-  set --local brightness_increased (math $brightness - $amount)
-  echo $brightness_increased | sudo tee /sys/class/backlight/*/brightness > /dev/null
-end

ansible/roles/fish/files/fish/functions/increase_brightness_by.fish

@@ -1,5 +0,0 @@
-function increase_brightness_by --argument-names amount
-  set --local brightness (cat /sys/class/backlight/*/brightness)
-  set --local brightness_increased (math $brightness + $amount)
-  echo $brightness_increased | sudo tee /sys/class/backlight/*/brightness > /dev/null
-end

ansible/roles/fish/files/fish/functions/set_brightness.fish

@@ -1,3 +0,0 @@
-function set_brightness --argument-names amount
-  echo $amount | sudo tee /sys/class/backlight/*/brightness > /dev/null
-end