Rename deprecated config option to enable_reloading in dev env (#30577)

config/environments/development.rb

@@ -8,7 +8,7 @@ Rails.application.configure do
   # In the development environment your application's code is reloaded any time
   # it changes. This slows down response time but is perfect for development
   # since you don't have to restart the web server when you make code changes.
-  config.cache_classes = false
+  config.enable_reloading = true
 
   # Do not eager load code on boot.
   config.eager_load = false