Add Deserialization section on guides at ActiveJob Exception [ci skip]

We should assign parameters to the request object rather than mutate the
hash that is returned by `query_parameters` or `request_parameters`

this prevents mutations from being available globally

Instead of trying to manually clear out a request object, lets just
allocate a new one.  The rack ENV is reused and cleaned (still), but the
request object is not.

[ci skip]

We should leverage the request / response objects that the superclass
has already allocated for us.

Support explicit defintion of resource name for collection caching.

Add method call assertions for internal use.

Add `assert_called` and `assert_not_called` to boil down the boilerplate we need to write
to assert methods are called certain number of times.

There is no reason to "recycle" response objects when we can just
allocate a new one.

[ci skip] Add `bundle exec` to Running a Single Test

marking serialization class in Readme

Adding brackets to array in docs

Variants are typically set in the controller based on some attribute of
the request that the browser sent.  We should make our tests more in
line with reality by doing the same and not mutating the request object.

we should be pushing the cookies in via headers rather than maintaining
some object and "recycling" it.

If a template includes `# Template Collection: ...` anywhere in its
source, that name will be used as the cache name for the partial that is
rendered for the collection.

This allows users to enable collection caching even if the template
doesn't start with `<% cache ... do %>`.

Moreover, the `# Template Collection: ...` notation is recognized in all
template types (and template types other than ERB can define a
resource_cache_call_pattern method to allow the `cache ... do` pattern
to be recognized too).

This reverts commit f2a8c236, reversing
changes made to 3046c9bb.

When preload is used in a default scope the preload_values were
returning nested arrays and causing the preloader to fail because it
doesn't know how to deal with nested arrays. So before calling preload!
we need to splat the arguments.

This is not needed to includes because it flatten its arguments.

[ci skip]

Closes #20792.

Custom validation methods are implemented in terms of
callbacks. The `validate` callback chain can't be halted using return
values of individual callbacks.

[ci skip]

While this :nodoc: did hide the constant it also removed the following
methods from the API docs:

- #attribute_method?
- #clear_validators!
- #validate
- #validators
- #validators_on

Those are public API and should be visible.

Issue was caused by dee4fbc9

/cc @zzak

Update CHANGELOG.md [ci skip]

Test proving that accepts_nested_attributes_for is secure against ID tampering attacks

Allow filtering params based on parent keys

Add to Security guides the secrets.yml [ci skip]

Add to RDoc of OrderedOptions the bang info [ci skip]