feat: update billing middleware

Author: mychidarko

src/docs/utils/billing.md

@@ -563,8 +563,8 @@ Leaf billing comes with a middleware that you can use to protect your routes bas
 | `billing.subscribed:plan-name` | Protect a route to only allow users subscribed to a specific plan |
 | `billing.not-subscribed` | Protect a route to only allow users who aren't subscribed |
 | `billing.not-subscribed:plan-name` | Protect a route to only allow users not subscribed to a specific plan |
-| `billing.trial` | Protect a route to only allow users on a trial period |
-| `billing.not-trial` | Protect a route to only allow users not on a trial period |
+<!-- | `billing.trial` | Protect a route to only allow users on a trial period |
+| `billing.not-trial` | Protect a route to only allow users not on a trial period | -->
 
 You can use these middlewares in your routes like this:
 
@@ -577,7 +577,7 @@ app()->get('/protected', [
 ]);
 
 app()->get('/protected', [
-    'middleware' => 'billing.not-subscribed',
+    'middleware' => 'billing.not-subscribed:Starter',
     'SubscriptionController@subscribe'
 ]);
 ```
@@ -586,10 +586,21 @@ If you want to customize what the middleware does if the user is not allowed to
 
 ```php:no-line-numbers [index.php]
 billing()->middleware('billing.subscribed', function () {
-    response()->redirect('/billing/subscribe');
+    response()->redirect('/some-special-page');
 });
 ```
 
+And then you can use the middleware like this:
+
+```php [_some-route.php]
+app()->get('/protected', [
+    'middleware' => 'billing.subscribed',
+    function() {
+        return 'You are subscribed';
+    }
+]);
+```
+
 <!-- ## Billing Currency
 
 PayStack is only available in Africa, and relies on local currency. Stripe is available globally and supports multiple currencies, so Leaf's billing allows you to set your currency in your `.env` file.