Update statistics.rake deprecation message

> This deprecation warning will be visible starting with the release of Rails 8.0,
so it seems correct to use "in Rails 8.1" instead of "in Rails 8.0".
@willnet

rails#47713 (comment)
rails#47713

Author: JuanVqz

railties/lib/rails/tasks/statistics.rake

@@ -36,7 +36,7 @@ task :stats do
   end.select { |name, dir| File.directory?(dir) }
 
   $stderr.puts Rails.deprecator.warn(<<~MSG, caller_locations(0..1))
-  `bin/rails stats` as rake task has been deprecated and will be removed in Rails 8.0.
+  `bin/rake stats` has been deprecated and will be removed in Rails 8.1.
   Please use `bin/rails stats` as Rails command instead.\n
   MSG