Not looking for other contributions like this, but I took the liberty
since I was already working on this.

Update URL in RELEASING_RAILS.md [ci skip]

* Update valid link for `signing release tag` from `git-scm` book
* Use `en`(English) instead of `tr`(Turkish) documentation link

The `Row` class is no longer used since d956772b.

Staled `@default_timezone` would cause an error on `reconnect!` after
`disconnect!`.

https://buildkite.com/rails/rails/builds/59495#23be8079-3a4f-4375-9991-0a6f874554f2

Steps to reproduce:

```
% ARCONN=postgresql bin/test test/cases/adapter_test.rb test/cases/base_test.rb -n "/(?:test_attributes_on_dummy_time|test_reconnect_after_a_disconnect)$/" --seed 15849
Using postgresql
Run options: -n "/(?:test_attributes_on_dummy_time|test_reconnect_after_a_disconnect)$/" --seed 15849

# Running:

.
E

Error:
ActiveRecord::AdapterTestWithoutTransaction#test_reconnect_after_a_disconnect:
NoMethodError: undefined method `add_coder' for #<PG::TypeMapAllStrings:0x00007f85ab9dd5b8>
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:866:in `update_typemap_for_default_timezone'
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:652:in `exec_no_cache'
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:636:in `execute_and_clear'
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:894:in `add_pg_decoders'
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:744:in `connect'
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:285:in `rescue in block in reconnect!'
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:281:in `block in reconnect!'
    /Users/kamipo/.rbenv/versions/2.6.1/lib/ruby/2.6.0/monitor.rb:230:in `mon_synchronize'
    /Users/kamipo/src/github.com/rails/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:280:in `reconnect!'
    /Users/kamipo/src/github.com/rails/rails/activerecord/test/cases/adapter_test.rb:465:in `block in <class:AdapterTestWithoutTransaction>'
```

Edit a changelog entry [ci skip]

Add additional ERB DummyCompiler tests

Change wording of some instances of 'opt out' [ci skip]

Update small typo in documentation.

This adds a few additional tests to the commits by eileencodes (https://github.com/rails/rails/pull/35497) and rafaelfranca (https://github.com/rails/rails/commit/cfa22f1a4b5e8b95ee01a432168de2f831b3f788). The additional tests cover several more ERB tag formatting cases such as multiline tags, conditional statements that result in duplicate keys, and multiple erb statements on a single line.

Show friendly message to install action mailbox if the related table does not exist

- This is similar to the work done in https://github.com/rails/rails/pull/31534

Fix warnings from Guides generation

After https://github.com/rails/rails/pull/35281  and https://github.com/rails/rails/pull/35036 AV warns about not having the compiled container.
Use the suggested with_empty_template_cache to overcome warning

Add note about has_many associations callbacks [ci skip]

Add a note explaining when the has_many associations callbacks will be called or not.

Add changelog entry for transliterate/parameterize accepting `locale` [ci skip]

Fall back to parent locale before falling back to the :errors namespace

overriden -> overridden [ci skip]

Add test for 'ActiveSupport::Inflector.transliterate'

Also add tests for parametrize and transliterate

Add `config.credentials.content_path` and `config.credentials.key_path` to the guide

This streamlines the lovely foundation Bogdan added. Mainly to add
guidance around encryption keys and remove some backticks.

Finally it adds some mention of how to access these files from Ruby
in apps.

[ Kasper Timm Hansen & bogdanvlviv ]

Improve output of `rails encrypted(:edit/:show) --help`

Add locale option to #parameterize

Parameterize is triggering I18n#transliterate. This method already
accepts a locale. It would be cleaner if similar to other string inflection
methods #parameterize also accepted 'locale' as a parameter.

Adds default trix content attachmment partial path

[ci skip] Fixed expanded option route example

Squish the deprecation messages across the codebase 

Sample example ->

Before:

prathamesh@Prathameshs-MacBook-Pro-2 blog *$ rails server thin
DEPRECATION WARNING: Passing the Rack server name as a regular argument is deprecated
and will be removed in the next Rails version. Please, use the -u
option instead.

After:

prathamesh@Prathameshs-MacBook-Pro-2 squish_app *$ rails server thin
DEPRECATION WARNING: Passing the Rack server name as a regular argument is deprecated and will be removed in the next Rails version. Please, use the -u option instead.

Mention `environment variable` instead of just `environment`