Merge pull request #16434 from strzalek/cookies-digest-config-option

Add digest config option for SignedCookiesJar
Revert "Merge pull request #16434 from strzalek/cookies-digest-config-option"

This reverts commit 705977620539e2be6548027042f33175ebdc2505, reversing
changes made to dde91e9bf5ab246f0f684b40288b272f4ba9a699.

IT BROKE THE BUILD!!!
Uppercase HTML in docs.

[skip ci]
Docs: grammar fix for fetch. [ci skip]
Merge pull request #16437 from mscoutermarsh/master

Docs: grammar fix for fetch. [ci skip]
Using delegated connection method
Pass block for logging.

This follows the good practice listed on http://guides.rubyonrails.org/debugging_rails_applications.html#impact-of-logs-on-performance.
[ci skip] Changed options to +options+ for rdoc
Update README.md

Ruby on Rails Tutorial link updated.
Merge pull request #16443 from duccioarmenise/patch-1

Rails Tutorial link updated
Merge pull request #16439 from voxxit/patch-1

Using delegated connection method
Merge pull request #16440 from tgxworld/pass_log_in_block

Pass block for logging.
Merge pull request #16441 from tomkadwill/activerecord_associations_options_param

[ci skip] Changed options to +options+ for rdoc
[ci skip] Fix sample code in engines guide
Merge pull request #16451 from y-yagi/patch-2

[ci skip] Fix sample code in engines guide
Cleanup Guides Guidelines [ci skip]

* Copy editing for clarity in several locations
* Rename "Titles" section to "Headings"
* Fix incorrect anchor in link to API Documentation Guidelines for filenames
Merge pull request #16453 from reshleman/re-cleanup-guides-guidelines

Cleanup Guides Guidelines [ci skip]
Merge pull request #16300 from vast/mention-changes-to-nil-serialization-in-upgrading-from-3.2

Mention changes to `nil` handling in serialized attributes
Fixed issue w/custom accessors + reserved name + inheritance

Fixed an issue where custom accessor methods (such as those generated by
`enum`) with the same name as a global method are incorrectly overridden
when subclassing.

This was partially fixed in 4155431 then broken again by e5f15a8.

Fixes #16288.
update error message to reflect that the record could have been destroyed