Update results of command in Testing guides [ci skip]

Refactor guides javascripts

* Remove `$` prefix from all variables (`$` prefix means jQuery object)
* Old browsers doesn't support forEach. So use for instead of forEach.

* Results of command in testing guides are different from actual ones.
* Updated them.

✂ jQuery for Rails Guides

Fix indentation manually

Rubocop auto-correct doesn't work well, so I fixed indentation manually.

Gracefully handle extra "controller" when generating controller

In the previous code incorrectly removes intermediate words.

Rubocop 0.54

Fix duplicated suffix for JobGenerator

Add test case to ChannelGeneratorTest

* Add a test case to ensure avoid duplicated suffix in channel generator

Reset RAW_POST_DATA between test requests

Follow up of #32514.

Fix .new with multiple through associations

Fix `.rubocop.yml: Lint/EndAlignment has the wrong namespace - should be Layout` warning

So `target.is_a?(Array)` is meaningless, and just use `target.empty?`
instead of `target.blank?`.

* Rewrite with Vanilla JS
* Confirmed with Chrome, Safari, Firefox

Relax assertions in connection config tests

At the moment these two ActiveRecord tests pass with `rake test:sqlite3`,
but fail with `ARCONN=sqlite3 bin/test`.

`Rails.root` is defined when running `bin/test`, but not when running
the rake task. When `Rails.root` is defined, `config[:database]` will
look something like `vagrant/rails/activerecord/db/primary.sqlite3`
instead of just `db/primary.sqlite3`.
(See https://github.com/rails/rails/blob/00caf95e14b90782ab17fbd6d2b930844df99980/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb#L27)

Relaxing `assert_equal` to `assert_match` will allow these tests to pass
regardless of how they are run.

I do have a question why we need both ways to run tests. I have been
using `bin/test` lately, but I see from #32426 that this is not the preferred
method.

`RAW_POST_DATA` is derived from the `rack.input` header, which changes
with each test request. It needs to be cleared in `scrub_env!`, or all
requests within the same test will see the value from the first request.

Preloading through polymorphic associations (still raises for typos on regular associations)

Add `touch_all` method to `ActiveRecord::Relation`

Create MissingExactTemplate exception with separate template

[ci skip] belongs_to in self join association needs optional: true, if it's over 5.0 ver of rails

[ci skip] Improve Rails::SourceAnnotationExtractor documentation

Allow `primary_key` argument to  `empty_insert_statement_value`

After renaming and deprecation of SourceAnnotationExtractor
documentation has been updated to reflect the new name Rails::SourceAnnotationExtractor

The previous documentation version listed only the default
registered extensions. This was misleading because if more extensions
get registered with
<tt>SourceAnnotationExtractor::Annotation.register_extensions</tt>,
they would be also taken into account. By saying that we consider
all registered extensions we document what happens in reality.

Fix typos related to ActionDispatch::Http::FilterParameters

Introduce ActionDispatch::DebugExceptions interceptors