Add an alias for reverse_merge to with_defaults

In the context of controller parameters, reverse_merge is commonly used
to provide defaults for user input. Having an alias to reverse_merge
called with_defaults feels more idiomatic for Rails.

Add comma and change verb.

[ci skip]

add hint on after_action filters

Load only needed records on ActiveRecord::Relation#inspect

Fix the example code for `Rails.groups` [ci skip]

CI against Ruby 2.2.7

FinderMethods#fourty_two docs cite proper source

Fix link to rails-ujs

[ci skip]

`Rails.groups` contains `Rails.env` that is inspected as String.

https://github.com/rails/rails-ujs is merged into actionview in favor of https://github.com/rails/rails/pull/28098.
[skip ci]

https://www.ruby-lang.org/en/news/2017/03/28/ruby-2-2-7-released/

silly method gets a silly doc fix, 
or I'm missing an even sillier joke and I'm about to get schooled.

BUT I'm pretty sure this is some serious Beaudrillard simulacrum, though.
I'm just doing my part to spread the gospel of Douglas Adams.

Adds a hint that ``after_action``-callbacks are not executed when an
exception was raised in the rest of the request cycle. The
``before_action`` section mentions "If there are additional filters
scheduled to run after that filter, they are also cancelled." but this
is IMO not sufficient.

Fix `primary_keys` across multiple schemas

This CHANGELOG.md is a continuation of the 5-1-stable one, there
shouldn't be any duplicate entries.

[ci skip]

Make `driven_by` overridable

Remove unnecessary `javascript` option check

Instead of loading all records and returning only a subset of those,
just load the records as needed.

Fixes #25537.

Sometimes we want to use rack_test partially instead of selenium for test speed:

```ruby
class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  driven_by :selenium, using: :chrome, screen_size: [1400, 1400], options: {url: "http://chrome:4444/wd/hub"}
end

class WithJavaScriptTest < ApplicationSystemTestCase
end

class WithoutJavaScriptTest < ApplicationSystemTestCase
  driven_by :rack_test
end
```

In the abobe case, `WithoutJavaScriptTest` uses selenium because
`SystemTestCase` calls superclass' driver on `#initialize` (`self.class.superclass.driver.use`).

Using `class_attribute` can handle inherited `driven_by`.

Follow up to #28546

Make internal methods to private

Add keep id suffix option to humanize new

No longer listens to dirs outside of the app directory.

Fix ActiveModel::Errors #keys, #values

Fix store accessors in parameters test

Before:
  person.errors.keys    # => []
  person.errors.values  # => []
  person.errors[:name]  # => []
  person.errors.keys    # => [:name]
  person.errors.values  # => [[]]

After:
  person.errors.keys   # => []
  person.errors.values # => []
  person.errors[:name] # => []
  person.errors.keys   # => []
  person.errors.values # => []

Related to #23468

make it clear how to enable caching

If a country doesn't exist in the MAPPINGS hash then create a new
`ActiveSupport::Timezone` instance using the supplied timezone id.

Fixes #28431.

The `master` changelog refer back to the `5-1-stable` changelog as a
base. No need to duplicate backported entries in the changelogs on
`master`.

With Rack::Test the headers needs to match the `HTTP_` format. The tests
were passing before because they are not asserting the response was a
cache hit.

Closes #28554

Merge pull request #28557 from y-yagi/remove_unnecessary_files_to_api_applications_when_app_task_task_executed

Remove unnecessary files to API-only Applications when `app:task` task executed

Remove -j (--javascript) option from `rails new`

Since 4.2 the default log level in production is now debug. We removed
the deprecation in c2e86584
but we don't reflected the default value. We are not appling it.

Closes #28558

Avoid converting integer as a string into float