Added method `#eql?` to `ActiveSupport::Duration`, in addition to `#==`.

Currently, the following returns `false`, contrary to expectation:

    1.minute.eql?(1.minute)

Adding method `#eql?` will make this behave like expected. Method `#eql?` is
just a bit stricter than `#==`, as it checks whether the argument is also a
uration. Their parts may be different though.

    1.minute.eql?(60.seconds)  # => true
    1.minute.eql?(60)          # => false
Update RecordNotFound exception cases to include a message with the
Model that the Record was not found in.
Roll back open transactions when the running thread is killed.
Changed the DangerousAttributeError exception message to include messaging that the conflict could be because of a conflicting attribute.
Explain ERB space removal. [ci skip]
Changes default render behavior from file to template.
MessageVerifier raises an appropriate exception if the secret is nil


Otherwise this will lead to another error later on 
when generating a signature:
TypeError (no implicit conversion of nil into String).
Globalid was released
Changes "if secret.nil?" to unless secret in MessageVerfier
Merge pull request #16897 from kostia/message-varifier-raises-exception-on-nil-secret

MessageVerifier.new raises an appropriate exception if the secret is nil
Change gid calls to to_gid
Se the test order of activejob tests
Prepare maintenance policy for 4.2 release [ci skip]
Merge pull request #16669 from aantix/dangerous_attribute_error_better_message

Improved the error messaging for the DangerousAttributeError exception
Change ActiveJob test directory to "test/jobs"
Merge pull request #16908 from y-yagi/change_activejob_test_dir

Change ActiveJob test directory to "test/jobs" [ci skip]
use `allow_blank` option instead
Revert "Merge pull request #15312 from JuanitoFatas/action_view/asset_path"

This reverts commit 21ec7fefea5a1b823cb88733b019b3d52240801d.

Per #16911, there's actually a good reason for a "blank" value to have a
useful `to_s` here. So let's also add some tests to prove that.
Merge pull request #13656 from chanks/rollback_transactions_in_killed_threads

Data corruption risk: Roll back open transactions when the running thread is killed.
Merge pull request #16910 from kuldeepaggarwal/use-rails-options

use `allow_blank` option instead of custom condition