Rename #source_extract to #source_extracts in ExceptionWrapper

Don't double check trace origin in ExceptionWrapper#traces

Don't show full trace on routing errors

If a trace isn't an application one, then it comes from a framework.
That's the definition of framework trace. We can speed up the traces
generation if we don't double check that.

Since dbcbbcf2 the full trace is shown
by default on routing errors. While this is a nice feature to have, it
does take the attention off the routes table in this view and I think
this is what most of the people look for in this page.

Added an exception to the default trace switching rule to remove that
noise.

add Nokogiri to docs generation guides [ci skip]

It returns multiple source extracts since 1ed264bc. Also cleaned its
result structure, as we no longer need the file in a code extract.

[ci skip] Missing space in Active Job guide for referring to Action Mailer

Don't let #{application,framework,full}_trace be nil

Those three can be nil when exception backtrace is nil. This happens and
that forced a couple of nil guards in the code. I'm proposing to make
those always return an array, even on nil backtrace.

[ci skip] add "Qu" to Backends Features list

`default_proc` makes a hash unmarshallable, and adds unneccessary
overhead. Since we control all access to the hash, let's just handle it
in that method. This has the side effect of improving performance on
initialization (but not neccessarily on access). We'll need to profile
further once the tests are passing.

In real usage, we give the builder a types hash with a default value of
`Type::Value.new`. This means we need to explicitly check for the key,
rather than the truthiness of the type to determine if it's a known but
uninitialized attribute

We don't know which attributes will or won't be used, and we don't want
to create massive bottlenecks at instantiation. Rather than doing *any*
iteration over types and values, we can lazily instantiate the object.

The lazy attribute hash should not fully implement hash, or subclass
hash at any point in the future. It is not meant to be a replacement,
but instead implement its own interface which happens to overlap.

This reverts commit 8fee9238.

Conflicts:
	activerecord/lib/active_record/attribute_set/builder.rb

This solution sucks, and is hard to actually apply across the board.
Going to try other solutions

Simplify and fix grammar [ci skip]

[skip ci]

Build fix when running in isolation

There is a significant performance difference between the two. Closes

Add basic tests for ActionDispatch::ExceptionWrapper

`Computer` class needs to be require

See #17217 for more details

[ci skip] Corrections to testing guide.

Partially revert https://github.com/rails/rails/commit/c31e638a37946a120f6dbf207127d36beea5ab85.

[ci skip] Remove deprecated testing tasks

This has changed recently and so rake test:all and rake
test:all:db are deprecated.

also increase the version of pg required so that people will get the
GVL friendly version

[ci skip] Improve upon testing tasks guide

Add missing testing tasks and also improve upon tasks descriptions

[ci skip] Capybara added to other testing approaches

name keywords

Abstract encoding strategy for ActiveSupport::MessageVerifier