Refactor of ::Rails module

Use sprockets-rails 2.0.0

Drop extra variable from test

Fix typos in AR changelog [ci skip]

Warning removed for Minitest

Grammar fix [ci skip]

1. Used ActiveSupport::Autoload to dry-up the autoload definitions.
2. Used ActiveSupport's delegate to dry up the application proxied
   attributes.
3. Did a little white space change on Rails.groups.

Fixed typos in activesupport [ci skip]

fix ActiveModel::Validations.validators_on doc

Don't blindly call blame_file! on exceptions in ActiveSupport::Dependes::Loadable

It is possible under some environments to receive an Exception that is
not extended with Blamable (e.g. JRuby).
ActiveSupport::Dependencies::Loadable#load_dependency blindly call
blame_file! on the exception which throws it's own NoMethodError
exception and hides the original Exception.

This commit fixes #9521

Remove column restrictions for `#count`, let the database raise if the SQL is invalid.