- Replace http with https
- Replace www.ruby-doc.org with ruby-doc.org

Replace the primary key type `integer` in docs with `bigint`.

ref #26266

Follow up to #22642.

Even though this means more things to change when we bump after a
release, it's more important that our examples are directly copyable.

If we use a real version, at best that'll be an onerous update required
for each release; at worst, it will encourage users to write new
migrations against an older version than they're using.

The other option would be to leave these bare, without any version
specifier. But as that's just a variant spelling of "4.2", it would seem
to raise the same concerns as above.

According to pr #22443 in the guides there's always a dollar sign before every command, so why is in the main README a `$` and in every submodule a `%`?

Just eye candy..

The **(11)** does not affect the storage size of the data type, which for an
INT will always be 4 bytes. It affects the **display width**.

http://www.tocker.ca/2015/07/02/proposal-to-deprecate-mysql-integer-display-width-and-zerofill.html

For Inline formats, changed ` (single backticks)   to <tt> tag at active record rdoc as single backticks (`) don't work with rdoc. for inline format.

I think we are better off leaving `sudo` outside of the documented
way of installing gems (`activerecord`, `actionpack`, …).

We don’t want newbies to think that `sudo` is required or, even worse, than
they actually have to type `[sudo] gem install`.

In most scenarios, `sudo` is not needed to install gems, and people who do
need it, probably already know about it.

What do you think? 😁

the issue tracker. See also #15455 [ci skip]

Don't make free form text appear in code blocks [ci skip]

ActiveRecord::Observer was extracted into a separate gem so it
should not be referenced anymore (see https://github.com/rails/rails/commit/ccecab3)

This reverts commit 14fc8b34.

Reason: we need to discuss a better path from this removal.

Conflicts:
	activerecord/lib/active_record/reflection.rb
	activerecord/test/cases/base_test.rb
	activerecord/test/models/developer.rb

This feature adds a lot of complication to ActiveRecord for dubious
value. Let's talk about what it does currently:

class Customer < ActiveRecord::Base
  composed_of :balance, :class_name => "Money", :mapping => %w(balance amount)
end

Instead, you can do something like this:

    def balance
      @balance ||= Money.new(value, currency)
    end

    def balance=(balance)
      self[:value] = balance.value
      self[:currency] = balance.currency
      @balance = balance
    end

Since that's fairly easy code to write, and doesn't need anything
extra from the framework, if you use composed_of today, you'll
have to add accessors/mutators like that.

Closes #1436
Closes #2084
Closes #3807

minor

see: https://github.com/blog/738-sidejack-prevention-phase-2-ssl-everywhere