Use `Array#wrap` instead `Array()`

[ci skip]

Closes #13566

Closes #13565

Lazy loading the tzinfo library doesn't really buy us anything because
the gem is installed as a dependency via the gemspec and if a developer
is using Active Support outside of Rails then they can cherry pick which
files to load anyway.

Fixes #13553

2014 is here.

Fix for #13437

Conflicts:
	activerecord/CHANGELOG.md

Update grant statement to address #13549

Avoid raising a NameError on FreeBSD using Date

[ci skip] Add missing flash message in block filter example.

The Date object has a xmlschema method starting with Ruby 1.9 so we were
assuming that we could safely remove this method and redefine it later
but the call to remove_method throws a NameError on FreeBSD so we should
rely on remove_possible_method instead.

This call is actually needed to avoid warnings when running the test
suite.

Fixes #11723

Also make all three examples consistent.

Fix comment syntax

Example:

    # application routes.rb
    mount BlogEngine => '/blog'

    # engine routes.rb
    get '/welcome' => redirect('')

This now redirects to the path `/blog`, whereas before it would redirect
to the application root path. In the case of a path redirect or a custom
redirect if the path returned contains a host then the path is treated as
absolute. Similarly for option redirects, if the options hash returned
contains a `:host` or `:domain` key then the path is treated as absolute.

Fixes #7977

The code syntax in the comment example is invalid

to make this grant statement described in the document works

GRANT ALL PRIVILEGES ON inexistent_activerecord_unittest.* to 'rails'@'localhost';

Add the ability to nullize the enum column

Add any/all support for variants

- since `Array()` calls `to_ary` or `to_a` on a subject
- the intent is to 'wrap' subject into an array

Make outer joins on proper parent

Allows you to check if a field has changed to a particular value

Outer joins were being built on the root relation klass rather than the
one specified in the join dependency root

Allow "url" sub key in database.yml configuration

https://github.com/rails/rails/commit/2075f39d726cef361170218fd16421fc52bed5a8 introduced a regression in includes/preloades
by calling `read_attribute` on an association when preloading takes places, instead of using loaded records in `association.target`.

tl;dr

Records are not made properly available via `read_attribute` when preloding in simultaneous,
but value of `@loaded` is already set true, and records concatenated in `association.target` on an association object.
When `@loaded` is true we return an object of `AlreadyLoaded` in preload_for. In `AlreadyLoaded` to return preloaded
records we make wrong use of `read_attribute`, instead of `target` records.

The regression is fixed by making use of the loaded records in `association.target` when the preloading takes place.

Fixes #13437

Currently a developer can pass in a YAML configuration that fully specifies connection information:

```
production:
  database: triage_production
  adapter: password
  pool: 5
```

They can also pass in a string that specifies a connection URL directly to an environment key:

```
production: postgresql://localhost/foo
```

This PR allows the use of both a connection url and specifying connection attributes via YAML through the use of the "url" sub key:

```
production:
  url: postgresql://localhost/foo
  pool: 3
```

This will allow developers to inherit Active Record options such as `pool` from `&defaults` and still use a secure connection url such as `<%= ENV['DATABASE_URL'] %>`. The URL is expanded into a hash and then merged back into the YAML hash. If there are any conflicts, the values from the connection URL are preferred. 

Talked this over with @josevalim

[ci skip] ConnectionSpecification::Resolver Docs

Document the internal interfaces of `ConnectionSpecification::Resolver`

Change method name from `config` to `env` to better match the most common use case.

Update explanation to match example [ci skip]

Add a missing changelog entry for #13534 [ci skip]