add cursor trail

modules/home-manager/terminal/kitty.nix

@@ -8,6 +8,7 @@ in
       enable = true;
       settings = {
         cursor = "#c7c7c7";
+        cursor_trail = 3;
         cursor_text_color = "#feffff";
         selection_foreground = "#3e3e3e";
         selection_background = "#c1ddff";