Use consistent bash5 style for conditionals and quoting

bin/omarchy-font-set

@@ -5,7 +5,7 @@
 
 font_name="$1"
 
-if [[ -n "$font_name" ]]; then
+if [[ -n $font_name ]]; then
   if fc-list | grep -iq "$font_name"; then
     if [[ -f ~/.config/alacritty/alacritty.toml ]]; then
       sed -i "s/family = \".*\"/family = \"$font_name\"/g" ~/.config/alacritty/alacritty.toml