[12.x] Carbon import (#10611)

* Update billing.md

* Update pennant.md

Author: AhmedAlaa4611

billing.md

@@ -1755,7 +1755,7 @@ This method will set the trial period ending date on the subscription record wit
 The `trialUntil` method allows you to provide a `DateTime` instance that specifies when the trial period should end:
 
 ```php
-use Carbon\Carbon;
+use Illuminate\Support\Carbon;
 
 $user->newSubscription('default', 'price_monthly')
     ->trialUntil(Carbon::now()->addDays(10))

pennant.md

@@ -523,7 +523,7 @@ Of course, feature scopes are not limited to "users". Imagine you have built a n
 
 ```php
 use App\Models\Team;
-use Carbon\Carbon;
+use Illuminate\Support\Carbon;
 use Illuminate\Support\Lottery;
 use Laravel\Pennant\Feature;