Conflicts:
	actionpack/lib/action_controller/metal/mime_responds.rb
	actionview/lib/action_view/vendor/html-scanner/html/sanitizer.rb
	activerecord/lib/active_record/type/value.rb

Small grammar fix in pluck description

Do not depend on queue_classic on JRuby

4.2 Release Notes pass [ci skip]

[ci skip] config.active_record.errors_in_transactional_callbacks -> config.active_record.raise_in_transactional_callbacks

[ci skip] Update plugin doc with the latest rails

[ci skip] Removed unnecessary word from Getting Started

[ci skip] config.active_record.errors_in_transactional_callbacks -> config.active_record.raise_in_transactional_callbacks

Make sure :checkout_timeout and :dead_connection_timeout are numbers
Conflicts:
	activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

Remove to_s from reflection.type in add_constraints

The instance var is already saved as a string in the initialization
method of AssociationReflection.

See https://github.com/rails/rails/blob/master/activerecord/lib/active_record/reflection.rb#L273

Fix after_commit warning message

Fix broken link to Upgrading Ruby on Rails Guide [ci skip]

in the 4.2 Release Notes [skip ci]

Change to link suggested by @zzak [skip ci]

Fixes #15821.