ActiveRecord #second_to_last tests and finder methods

Merge pull request #22170 from samphilipd/sam/properly_deallocate_prepared_statements_outside_of_transaction

 Correctly deallocate prepared statements if we fail inside a transaction

`OptimizedFileSystemResolver` (which most Rails apps use), but did not
implement the feature on the more generic `PathResolver`, which is often
used in tests etc.

Fixes #23881

Active Job: pare down async adapter for low footprint dev

Updating the dummy app template to have rails_command instead of rake

Remove inconsistency in the Action Cable README

Use one shared worker pool for all queues with 0-#CPU workers rather
than separate pools per queue with 2-10*#CPU workers each.

When the `source_type` option is passed to a has_many through, the
resulting `Reflection` will be an instance of `PolymorphicReflection`
and not `ThroughReflection`, meaning that it will ignore the scopes that
it needs to apply from the through reflections. This adds an additional
delegation call to remedy this. I've been finding the reflection code
completely impenetrable lately, it could use some major love.

Fixes #22726

Run CI for ActionPack on JRuby

Removes potentially quadratic Regexp from ActiveRecord::LogSubscriber…

Honour joining model order in `has_many :through` associations when
eager loading

Drop Action Controller require in ActionDispatch::ExceptionWrapper

Add documentation for #13897 [skip ci]

Fix value of CSS background-color property in Ruby on Rails guide

We only reference the Action Controller error classes by name in
ActionDispatch::ExceptionWrapper, so there is no need to explicitly
require them.

It drops a tiny coupling between Action Dispatch and Action Controller,
so it makes me feel warm inside. We still have a lot of others AC
requires in the AD code base, but here, we can save it.

[ci skip]

Having more readable test descriptions in railties actions_test.rb

Changed description with tests related to rails_command.

Fix typos in Rails guide about Action View Overview

This patch fixes some typos in the Action View Overview section of the Rails guide.

[ci skip]

Change background-color value to transparent, which is the default value of background-color.

[ci skip]

Address ruby warnings

- Ambiguous first argument
- Mismatched indentation

add `constraint_to` option to SSL middleware

Update deprecation message shown when tasks from rails namespace are run

Fix formatting in Action Cable guide [ci skip]

Fix merge conflict in Action Cable guide [ci skip]

remove "rake" word [ci skip]

Fix typos in Action Cable guide [ci skip]