Correctly handle limit on int4 and int8 types in PG

PG doesn't register it's types using the `int(4)` format that others do.
As such, if we alias `int8` to the other integer types, the range
information is lost. This is fixed by simply registering it separately.

The other option (which I specifically chose to avoid) is to pass the
information of the original type that was being aliased as an argument.
I'd rather avoid that, since an alias should truly be treated the same.
If we need different behavior for a different type, we should explicitly
register it with that, and not have a conditional based on aliasing.

Fixes #18144

[Sean Griffin & ysbaddaden]
Do not use line breaks on notes [ci skip]

References #18138
Add `force: true` to table created in tests

If the test is interrupted in a way that the teardown block fails to
run, the tests will fail to run until the table is removed manually
without this option.
Only add debugger/byebug if on MRI
Merge pull request #18149 from arthurnn/byebug_on_mri

Only add debugger/byebug if on MRI
Skip byebug on all non-MRI rubies, fix tests

The changes in #18149 added tests for the app generator, but only fixed
it for the plugin generator (I should have let CI finish though I think
it would have failed as an allowed failure).
Convert `references` to kwargs

While we aren't taking PRs with these kinds of changes just yet, they
are fine if we're actively working on the method and it makes things
easier.
Add a `foreign_key` option to `references` while creating the table

Rather than having to do:

    create_table :posts do |t|
      t.references :user
    end

    add_foreign_key :posts, :users

You can instead do:

    create_table :posts do |t|
      t.references :user, foreign_key: true
    end

Similar to the `index` option, you can also pass a hash. This will be
passed as the options to `add_foreign_key`. e.g.:

    create_table :posts do |t|
      t.references :user, foreign_key: { primary_key: :other_id }
    end

is equivalent to

    create_table :posts do |t|
      t.references :user
    end

    add_foreign_key :posts, :users, primary_key: :other_id
Convert `add_references` to use kwargs

While we still aren't accepting PRs that only make changes like this,
it's fine when we're actively working on a method if it makes our lives
easier.
Add `foreign_key` as an option to `references` for `change_table`

This has the same comments as 9af90ffa00ba35bdee888e3e1ab775ba0bdbe72c,
however it affects the `add_reference` method, and `t.references` in the
context of a `change_table` block.

There is a lot of duplication of code between creating and updating
tables. We should re-evaluate the structure of this code from a high
level so changes like this don't need to be made in two places. (Note to
self)
Use the new `foreign_key` option on `references` in generators

Changes `rails g model Post user:references` from

    def change
      create_table :posts do |t|
        t.references :user, index: true
      end

      add_foreign_key :posts, :users
    end

to

    def change
      create_table :posts do |t|
        t.references :user, index: true, foreign_key: true
      end
    end

Changes `rails g migration add_user_to_posts user:references` from

    def change
      add_reference :posts, :users, index: true
      add_foreign_key :posts, :users
    end

to

    def change
      add_reference :posts, :users, index: true, foreign_key: true
    end
Add test missed by a03ea684efc3505647cf0327a501aa2dbb591ad2
Don't wrap `create_table` in a transaction for tests which run on MySQL

PG will warn without it, but mysql2 errors out.
Don't calculate all in-place changes to determine if attribute_changed?

Calling `changed_attributes` will ultimately check if every mutable
attribute has changed in place. Since this gets called whenever an
attribute is assigned, it's extremely slow. Instead, we can avoid this
calculation until we actually need it.

Fixes #18029
Don't perform statement caching for `find` when called from a scope

If there is a method defined such as `find_and_do_stuff(id)`, which then
gets called on an association, we will perform statement caching and the
parent ID will not change on subsequent calls.

Fixes #18117
Improve the performance of reading belongs_to associations

`ActiveRecord::Base#[]` has overhead that was introduced in 4.2. The
`foo["id"]` working with PKs other than ID isn't really a case that we
want to support publicly, but deprecating was painful enough that we
avoid it. `_read_attribute` was introduced as the faster alternative for
use internally. By using that, we can save a lot of overhead. We also
save some overhead by reading the attribute one fewer times in
`stale_state`.

Fixes #18151
Merge pull request #18147 from andreynering/guides-line-breaks-fix

Do not use line breaks on notes [ci skip]
Better tests for AV::RecordIdentifier

This commit intends to clarify the scope of ActionView::RecordIdentifier
methods `dom_id` and `dom_class`.

Most of the current documentation comes from da257eb8 (7 years ago) when
the decoupling of ActionView, ActiveRecord and ActiveModel was not a concern.

Since then, steps have been taken to reach such decoupling.
Therefore I think it's important to show that ActionView::RecordIdentifier
**does not strictly depend on the ActiveRecord API**:
any class `Post` implementing `post.to_key` and `post.model_name.param_key`
will work.

This commit adds a test to prove that ActionView::RecordIdentifier methods
can also be used on objects that do not subclass ActiveRecord::Base.
Merge pull request #18156 from claudiob/better-record-identifier-tests

Better tests for AV::RecordIdentifier
Don't raise on out-of-range datetimes passed by a user