Standardize on `Rails.application` [ci skip]

This seems to be the style settled on in most of the templates.
ActiveRecord CHANGELOG improvements [skip ci]
Merge pull request #16987 from jonatack/patch-8

ActiveRecord CHANGELOG improvements [skip ci]
[ci skip] modify the description of production log level default
Merge pull request #16988 from y-yagi/chg_default_log_level

[ci skip] modify the description of production log level default
Fix typo [ci skip]
Merge pull request #16994 from yuki24/fix-typo-in-ar-attribute-method-test

[ci skip] Fix typo in activerecord/test/cases/attribute_methods_test.rb:737
Merge pull request #16979 from square/standardize-call-style

Standardize on `Rails.application` [ci skip]
Document that the default for `rails server -b` has changed

Fixes #16578
Merge pull request #16984 from chancancode/fix_16578

Document that the default for `rails server -b` has changed
Fix assertions in AR::TestCase::AttributeMethodsTest

This test has always been green because it uses "assert" and the first
argument is an truthy class/object.
Merge pull request #16998 from yuki24/fix-false-assertion

Fix false assertions in AR::TestCase::AttributeMethodsTest
Fix another false assertions

 * The assertions in AS::Duration don't actually assert.
 * The assertion in Railtie will pass even when `eager_load_namespaces`
   doesn't include `AppTemplate::Application` if `Rails.application` is
   truthy.

For more details, see here:

 * https://github.com/rails/rails/pull/16998
 * https://github.com/rails/rails/pull/17000
Wrap Adequate Record release notes at 80 chars [ci skip]
Wrap it up! :trollface: [ci skip]
Merge pull request #17000 from yuki24/fix-false-assertions

Fix another false assertions
Remove wrapping <div> in form helpers from doc

[ci skip]

89ff1f8 and 1de258e6 removed from the HTML generated by the form helpers
the <div> that was wrapping the field elements inside the <form>.

This commit updates the documentation of the methods to reflect the
two commits above.
Merge pull request #17001 from claudiob/remove-wrapping-div-from-form-helpers-doc

Remove wrapping <div> in form helpers from doc [ci skip]