[Testing guide] Use "Fixtures API" instead of "fixture api".
[Testing guide] Using "Fixtures API" consistently

- In guides, "API" is used consistently instead of "api".
- Reason behind replacing "fixtures API" to "Fixtures API" is because
  here we are referring to the concept of "fixtures". In other places in
  the guide "fixture" OR "fixtures" is referred to the single or
  multiple instances of test data.
- This is also followup of https://github.com/rails/docrails/commit/aa9d1332b20305dd860b21a7ada06c5252bebad5#commitcomment-8497376.
Fix grammar on ActiveRecord::AttributeMethods doc.

[ci skip]
allow 'all' for :domain option in addition to :all
Don't remove mailer layouts files
Remove custom errors page section from the guides

This pattern is too problematic and introduces a lot of edge cases:

  * On 4.2, the issue https://github.com/rails/rails/issues/15124 is
    back again.
  * needs to define each action for each http status otherwise the
    router raises ActionController::RoutingError (No route matches).
  * If the router has `match "/*username",...` and some action is
    missing, Rails will pick up the "match" and try to do its job.
  * encourages people to copy & paste programming. Not DRY.

[ci skip]
Fix Sidekiq ActiveJob integration setup

* .connect on a Redis connection wasn't valid
* Reset logger after we're done testing for redis connection to avoid
  "closed stream" error when starting server for real from a fork
make OR in journey patterns compile to a valid regular expression
Hide potentially sensitive ActiveJob params from logs

* Show GlobalID instead of full object .inspect output
Merge branch 'master' of github.com:rails/rails
FIX: absolute_path may be nil for code added via instance_eval
Merge pull request #17860 from SamSaffron/fix_engine_backtrace

FIX: absolute_path may be nil for code added via instance_eval
Pretty-print request params on exception page
Ensure numericality validations work with mutation

The detection of in-place changes caused a weird unexpected issue with
numericality validations. That validator (out of necessity) works on the
`_before_type_cast` version of the attribute, since on an `:integer`
type column, a non-numeric string would type cast to 0.

However, strings are mutable, and we changed strings to ensure that the
post type cast version of the attribute was a different instance than
the before type cast version (so the mutation detection can work
properly).

Even though strings are the only mutable type for which a numericality
validation makes sense, special casing strings would feel like a strange
change to make here. Instead, we can make the assumption that for all
mutable types, we should work on the post-type-cast version of the
attribute, since all cases which would return 0 for non-numeric strings
are immutable.

Fixes #17852
Merge pull request #17861 from kirs/pp-request-params

Pretty-print request params on exception page
Fix value extracted from negative integers for PostgreSQL.

Fixes: https://github.com/rails/rails/issues/17856.
Merge pull request #17863 from tgxworld/fix_extracated_default_value_for_negative_integers

Fix value extracted from negative integers for PostgreSQL.
tests, use public API to verify default parsing. #17863, #17856
tests, run numeric default tests for every adapter.
Merge pull request #17827 from rkh/rkh-fix-or-pattern

Fix OR in Journey patterns