remove extra newline from ApplicationJob template

[ci skip] Replace `query methods` with `a predicate`

Fix doc: set_callback also accepts an array of if:

When Active Record calls `set_callback` inside `after_commit`,
[these lines of code](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/transactions.rb#L276)
pass an **array** of methods as the `:if` condition:

```ruby
options[:if] = Array(options[:if])
options[:if] << "transaction_include_any_action?(#{fire_on})"
```

That made me realize that anyone could pass an **array** of `:if` and `:unless`
conditions to `set_callback`, since Active Support transforms these conditions
into an array anyways in [these lines of code](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/callbacks.rb#L365):

```ruby
@if      = Array(options[:if])
@unless  = Array(options[:unless])
```

Long story short, this commit updates the documentation of the `set_callback`
method to explain that arrays are also accepted.

It also replaces +false+ and +true+ with false and true, since any _falsey_ or
_truthy_ value will work.

[ci skip]

rename `widgets` table to `new_widgets`

    `widgets` table is being created in `primary_keys_test.rb` for PostgreSQLAdapter, MysqlAdapter, Mysql2Adapter
    and it makes test to fail earlier.

    Before:
      `bundle exec rake mysql2:test`

    ```
    Finished in 127.287669s, 35.5258 runs/s, 97.8885 assertions/s.

      1) Error:
    PersistenceTest::SaveTest#test_save_touch_false:
    ActiveModel::UnknownAttributeError: unknown attribute 'name' for #<Class:0x0000000a7d6ef0>.
        /home/kd/projects/kd-rails/activerecord/lib/active_record/attribute_assignment.rb:36:in `rescue in _assign_attribute'
        /home/kd/projects/kd-rails/activerecord/lib/active_record/attribute_assignment.rb:34:in `_assign_attribute'
        /home/kd/projects/kd-rails/activemodel/lib/active_model/attribute_assignment.rb:40:in `block in _assign_attributes'
        /home/kd/projects/kd-rails/activemodel/lib/active_model/attribute_assignment.rb:39:in `each'
        /home/kd/projects/kd-rails/activemodel/lib/active_model/attribute_assignment.rb:39:in `_assign_attributes'
        /home/kd/projects/kd-rails/activerecord/lib/active_record/attribute_assignment.rb:26:in `_assign_attributes'
        /home/kd/projects/kd-rails/activemodel/lib/active_model/attribute_assignment.rb:33:in `assign_attributes'
        /home/kd/projects/kd-rails/activerecord/lib/active_record/core.rb:293:in `initialize'
        /home/kd/projects/kd-rails/activerecord/lib/active_record/inheritance.rb:61:in `new'
        /home/kd/projects/kd-rails/activerecord/lib/active_record/inheritance.rb:61:in `new'
        /home/kd/projects/kd-rails/activerecord/lib/active_record/persistence.rb:50:in `create!'
        /home/kd/projects/kd-rails/activerecord/test/cases/persistence_test.rb:913:in `test_save_touch_false'

    4522 runs, 12460 assertions, 0 failures, 1 errors, 4 skips
    ```

    After:
      `bundle exec rake mysql2:test`

    ```
       Finished in 135.785086s, 33.3026 runs/s, 91.7774 assertions/s.

       4522 runs, 12462 assertions, 0 failures, 0 errors, 4 skips
    ```

Require Module#delegate core ext in ActiveModel::Naming

Combine complementary AR #find doc lines

Simplify and alias ActiveModel::Errors methods where possible

This reverts commit 9420de59.

Reason: Turns out we want to keep this method.

Add explicit base class for ActiveJob jobs

Test using sprockets 3

Replace `in Rails 4` with `in Rails %version%` in deprecation message

Deprecate the `:tokenizer` option to `validates_length_of`

As demonstrated by #19570, this option is severely limited, and
satisfies an extremely specific use case. Realistically, there's not
much reason for this option to exist. Its functionality can be trivially
replicated with a normal Ruby method. Let's deprecate this option, in
favor of the simpler solution.

Fixes #19568

We were never clearing the `PG::Result` object used to query the types
when the connection is first established. This would lead to a
potentially large amount of memory being retained for the life of the
connection.

Investigating this issue also revealed several low hanging fruit on the
performance of these methods, and the number of allocations has been
reduced by ~90%.

Fixes #19578

[ci skip] Fix an object of `reference`

use correct method in batches test

Return super in ActionController::Parameters.const_missing

The current implementation of ActionController::Parameters.const_missing
returns `ActionController::Parameters.always_permitted_parameters` even
if its `super` returns a constant without raising error. This prevents its
subclass in a autoloading module/class from taking advantage of
autoloading constants.

    class SomeParameters < ActionController::Parameters
      def do_something
        DefinedSomewhere.do_something
      end
    end

In the code above, `DefinedSomewhere` is to be autoloaded with
`Module.const_missing` but `ActionController::Parameters.const_missing`
returns `always_permitted_parameters` instead of the autoloaded
constant.

This pull request fixes the issue respecting `const_missing`'s `super`.

Remove old and not working link. [ci skip]

setup as block run before setup actlually runs so it will fail for our
case

We are promoting too much a feature that will not be widler used.
So for now lets keep just the ArrayInquirer constructor.

Provide friendlier access to request variants

 Improve CHANGELOG for fix for respecting pluralize_table_names [ci skip...

[skip ci] Improve `warn_on_records_fetched` code documentation

- ‘dection’ -> ‘detection’

- ‘exceeds threshold’ -> ‘exceeds the threshold’

- Other minor improvements.