Fix CheckPermission in docs

docs/guides/commands/samples/require_owner.cs

@@ -10,7 +10,7 @@ using System.Threading.Tasks;
 public class RequireOwnerAttribute : PreconditionAttribute
 {
     // Override the CheckPermissions method
-    public async override Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IServiceProvider services)
+    public async override Task<PreconditionResult> CheckPermissionsAsync(ICommandContext context, CommandInfo command, IServiceProvider services)
     {
         // Get the ID of the bot's owner
         var ownerId = (await services.GetService<DiscordSocketClient>().GetApplicationInfoAsync()).Owner.Id;