This reverts commit f6db31ec.

Reason:
Scope names can very easily conflict, particularly when sharing Concerns
within the team, or using multiple gems that extend AR models.

It is true that Ruby has the ability to detect this with the -w option, but the
reality is that we are depending on too many gems that do not care about Ruby
warnings, therefore it might not be a realistic solution to turn this switch on
in our real-world apps.

[ci-skip]

English explanation to multi-level nested join

Raise AR::IrreversibleOrderError when #reverse_order can not do it's job

Added an "Or, in English..." explanation to the "Joining Nested Associations (Multiple Level)" example.

Update sucker_punch adapter's description

Remove nonsense definition of == from `AcceptItem`.  The definition only
compared names and not `q` values or even object identity.  The only use
was in the `assort!` method that really just wanted the index of the
item given the item's name.  Instead we just change the caller to use
`index` with the block form.

This commit refactors the private methods that were just aliases to []
to just directly use [] and cache the return values on the stack.

same strategy as `@text_xml_idx`: cache it on the stack to avoid ivar
lookups and the `||=` call.

this eliminates the ivar lookup and also eliminates the `||=`
conditional that happens every time we called the `text_xml_idx` method.

[ci skip]

Update ActiveJob adapter for sucker_punch 2.0

Fix img alt attribute generation when using Sprockets >= 3.0

Fix typo in strong params hash deprecation message

and remove unecessary spaces in string interpolation.

The commit which originally added this behavior did not consider that
doing `Subclass.new` does not actually populate the `type` field in the
attributes (though perhaps it should). We simply need to not use the
defaults for STI related things unless we are instantiating the base
class.

Fixes #23285.

This PR includes two changes for 2.0.0:

- Breaking API change around `async.perform` --> `perform_async`
- New addition of `perform_in`, which now allows end users of the
  adapter to use the `enqueued_at` public API method.

Fix small typos in asset_pipeline.md

Improvement in ActiveRecord::Persistence doc [ci skip]

Fix doc

Revert "Eliminate the EventMachine dependency"

remove duplication section [ci skip]

Raises when #reverse_order can not process SQL order instead of making
invalid SQL before this patch

[ci skip]

We found that inserting all 600 schema_migrations for our mid-sized app takes about a minute on a cloud based CI environment.

I assume that the original code did not use multi-row-insert because SQLite3 was not supporting the syntax back then,
but it's been supported since 3.7.11: http://www.sqlite.org/releaselog/3_7_11.html

Fix undefined error for `ActionController::Parameters`

These tests were failing due to backwards incompatible changes, as apart
of the v1.0.3 release of rails-html-sanitizer.

The cache for `render file:` seems to also be used in the case of
`render(string)`.  If one is supposed to be a hit and the other is
supposed to be a miss, and they both reference the same file, then the
cache could return incorrect values.  This commit clears the cache
between runs so that we get non-cached behavior.

documentation fix