Fix alacritty window config

opacity wasn't registeres, because it wasn't inside the window object.
added y padding to push prompt a bit downwards

home/features/desktop/common/alacritty.nix

@@ -5,6 +5,13 @@
 }: {
   programs.alacritty.enable = true;
   programs.alacritty.settings = {
+    window = {
+      opacity = 0.83;
+      padding = {
+        x = 0;
+        y = 5;
+      };
+    };
     colors = with config.colorScheme.colors; {
       bright = {
         black = "0x${base00}";