Move to_param to to_query, also Improve tests
remove blank lines in the start of the ActiveRecord files
Merge pull request #16326 from itsNikolay/remove_blank_lines

remove blank lines at the start of the ActiveRecord files
Move object test files under object
Merge pull request #15658 from akshay-vishnoi/object-tests

Move object test files under object
Merge pull request #15629 from akshay-vishnoi/test-to_param

Define Hash#to_query and set Hash#to_param as alias to it; with test cases
Give password_confirmation div the "field" class in erb form template
Added failing test case for #16131
Fixed a compatibility issue with the `Oj` gem

`Time#as_json`, `Date#as_json` and `DateTime#as_json` incorrectly depends on a
delegation that is set up in `active_support/json/encoding`. We cannot simply
require that file in `core_ext/object/json` because it would cause a circular
dependency problem (see #12203 for background). We should instead rely on AS's
autoload to load that file for us on-demand.

To trigger autoload correctly, we need to reference the `AS::JSON::Encoding`
constant instead of using the delegated version.

Fixes #16131.
Raise an exception when attachments are added after `mail` was called.

Closes #16163

Adding attachments after a call to `mail` will result in invalid emails.
This is related to the fact, that `mail` is making the required preparations
before the email is ready to be sent. These change depending on your
added attachments.
Merge pull request #16148 from rails/fix_json_autoload

Fix json autoload
Merge pull request #16328 from noinkling/template_password_confirmation_fix

Give password_confirmation div the "field" class in the scaffold generator "_form" partial
[ci skip] fix doc typo for validates_uniqueness_of
Merge pull request #16332 from shizm/fix-docs-validates-uniqueness-of

[ci skip] fix doc typo for validates_uniqueness_of
Move array test files under array
docs, cleanup mixed indents within `form_options_helper.rb` RDoc.

[ci skip]

This fixes the broken code block rendering and indents the examples
within the parameter list.
Merge pull request #16334 from akshay-vishnoi/array-tests

Move array test files under array
Add missing test case for Array#to_sentence, collect all test cases for Object#to_param at one place and avoid repitition
Merge pull request #16336 from akshay-vishnoi/fix-tests

Add missing test case for Array#to_sentence, collect all test cases for Object#to_param at one place and avoid repitition
Get request should not write to database note added. [skip ci]