Conflicts:
	activerecord/test/cases/validations/association_validation_test.rb

Causes a double // in Dir.glob that breaks Ruby 2.2-trunk.
Not really a bug, but not relevant to this test either.

Originally added in ed21f0c5

/cc @tenderlove

PostgreSQL Timestamps always map to `:datetime`.

The PG Adapter should use `:datetime` consistently instead of mapping
mispellings to `:timestamp`.

See #14513

[ci skip] Improve formatting and yml

Fix a typo in the doc of forty_two AR FinderMethod [ci skip]

[ci skip] Improve readability of contributing to rails guide.

Fix railties asset tests: precompile the image we're referencing

You can't compile a file that references a non-compiled asset's path.

.. unless you turn off asset runtime errors.

Outside of a test case like this, `config.assets.precompile` would
normally retain its default entry, which precompiles all images (and
other non-JS/CSS files) that are in `app/assets`.

Move `NoTouching` down the inheritance chain on AR::Base

Closes #14841.

Fixed an issue with migrating legacy json cookies.

Previously, the `VerifyAndUpgradeLegacySignedMessage` assumes all incoming
cookies are marshal-encoded. This is not the case when `secret_token` is
used in conjunction with the `:json` or `:hybrid` serializer.

In those case, when upgrading to use `secret_key_base`, this would cause a
`TypeError: incompatible marshal file format` and a 500 error for the user.

Fixes #14774.

*Godfrey Chan*

Correct comment [ci skip]

This file is using this pattern already

Fix behavior of select! to be consistent with select #14752

Properly handle scoping with has_many :through. Fixes #14537.

Conflicts:
	activerecord/CHANGELOG.md
	activerecord/test/cases/associations/has_many_through_associations_test.rb

Fix inconsistent behavior from String#pluralize

Fix run-on sentences and improve grammar [skip ci]

Change favicon_link_tag helper mimetype from image/vnd.microsoft.icon to image/x-icon.

replace class_eval by define_method in abstract_controller/callbacks

Add test for using ActionView::Helpers::FormHelper.label with block and html

Fixes #14752

Select mimics the block interface of arrays, but does not mock the
block interface for select!. This change moves the api to be a
private method, _select!.

Although the official IANA-registered MIME type for ICO files is image/vnd.microsoft.icon,
registered in 2003, it was submitted to IANA by a third party and is not recognized by Microsoft products.
The MIME type image/x-icon should be used since is the one recognized by the major browsers on the market.

ActionController::Renderers documentation fix

Removed missleading comment [ci skip]

ActionController::Renderers::RENDERERS is an instance of Set. Docs incorrectly
state that it's a Hash.

After this 21dbe6f3

2.1.1 :001 > 'business'.classify
 => "Business"

2.1.1 :004 > 'calculus'.classify
 => "Calculu"
2.1.1 :005 >

correct the classify example's output.