Remove unnecessary return statements

These statements were automatically added by CoffeeScript.

I'm only removing the obvious cases; there might be more cases where the
`return` statement isn't necessary.

app/assets/javascripts/checkbox_toggle.js

@@ -1,15 +1,15 @@
-// Generated by CoffeeScript 1.12.6
 (function() {
   "use strict";
   App.CheckboxToggle = {
     initialize: function() {
-      return $("[data-checkbox-toggle]").on("change", function() {
+      $("[data-checkbox-toggle]").on("change", function() {
         var $target;
         $target = $($(this).data("checkbox-toggle"));
+
         if ($(this).is(":checked")) {
-          return $target.show();
+          $target.show();
         } else {
-          return $target.hide();
+          $target.hide();
         }
       });
     }