This reads a lot better, and we won't need to try start_with? for blank
delimiters.

Also rename method name to read better.

The conversion without area code already changed the passed number in
place, so change the other method to do the same.

Ruby's Date class automatically gives us #yesterday, #today,
and #tomorrow. And ActiveSupport has a handy Time.zone.today
for getting a localized version. But there was no localized
version of #yesterday or #tomorrow. Until now.

Modify the Hash#assert_valid_keys error message so that it shows the valid keys. Also, show the wrong value as it was entered.

{ :failore => "stuff", :funny => "business" }.assert_valid_keys([ :failure, :funny ])
=> ArgumentError: Unknown key: failore
{ 'failore' => "stuff", :funny => "business" }.assert_valid_keys([ :failure, :funny ])
=> ArgumentError: Unknown key: failore

{ 'failore' => "stuff", :funny => "business" }.assert_valid_keys([ :failure, :funny ])
=> ArgumentError: Unknown key: "failore". Valid keys are: :failure, :funny

{ :failore => "stuff", :funny => "business" }.assert_valid_keys([ :failure, :funny ])
=> ArgumentError: Unknown key: :failore. Valid keys are: :failure, :funny

Conflicts:
	activerecord/CHANGELOG.md

Closes #11624.

Also added the missing CHANGELOG entry for #12183 @ 80e75520 and
4d02296c.

Use the already existing strings instead of creating a new one each time
just to test if it responds to the methods.

[ci skip]

we’re using .delegate and should require it.

In Ruby 2.0.0-p353 there was a
[commit](https://github.com/ruby/ruby/commit/66915c507777c5e3a978fa73de25db763efd9206)
that switched case matching from actual sending `===` method to magic lookup,
that does not see it in `method_missing`. It's hard to predict how exactly and
when exactly this bug will be solved so here I suggest a solution of defining
it in Duration directly.

In Ruby 2.0.0-p353 without the added fix added test crashes to segmentation
fault.

Improve Module#delegate documentation to tell that delegate don't work with private or protected methods. [ci skip]

Extract **notable changes**, **deprecations** and **removals** from
each CHANGELOG.

I tried to reference the commits and pull requests for new features
and deprecations.

In the process I also made some minor changes to the CHANGELOGS.

The 4_1_release_notes guide is declared WIP.

Provide message to define ActiveSupport::TestCase.name instead.
Allow calling describe with a block, which Minitest::Spec does.