Add a section about job testing [ci skip]

* Cover lower level job testing (assertions about the execution of the
  job itself).
* Add a table with the custom assertions provided by Active Job's
  `TestHelper` module.
* Add an example testing job queuing inside a model
Delegate comparison operator to value
default scopes should break the cache on has_many.

if you specify a default scope on a model, it will break caching.  We
cannot predict what will happen inside the scope, so play it safe for
now.  fixes #17495
Merge pull request #17493 from petewest/duration-comparable

Delegate comparison operator to value
[ci skip] Fix line break on command line guide
default scopes should break the cache on singulur_association.

fixes #17495
Merge pull request #17476 from robin850/job-testing

Add a section about job testing [ci skip]
Merge pull request #17559 from alfa-jpn/fix/singular_association_cache

default scopes should break the cache on singulur_association.
Merge pull request #17557 from yui-knk/fix/command_line_guide

[ci skip] Fix line break on command line guide
Documenting Rails::Info module [ci skip]
Fix comment of SourceAnnotationExtractor#find_in

Commit(810af6f) changed which extensions are taken into account,
so make to match comment of find_in.
And sort extensions to follow the added order.
Merge pull request #17563 from yui-knk/fix/source_annotation_extractor

[ci skip] Fix comment of SourceAnnotationExtractor#find_in
[ci skip] Fix typo in command_line.md
Merge pull request #17564 from yui-knk/fix/command_line_guide

[ci skip] Fix typo in command_line.md
Ensure HABTM relationships produce valid class names (Fixes #17119)
Merge pull request #17217 from codeodor/fix-17119

Ensure HABTM relationships produce valid class names (Fixes #17119)
added description for rails generators, and fixed sentence formation for active_support/notifications [ci skip]
Merge pull request #17572 from rishijain/update_docs_10

Fixed grammar about AS::Notifications [ci skip]
Revert the behavior of booleans in string columns to that of 4.1

Why are people assigning booleans to string columns? >_>

We unintentionally changed the behavior on Sqlite3 and PostgreSQL.
Boolean values should cast to the database's representation of true and
false. This is 't' and 'f' by default, and "1" and "0" on Mysql. The
implementation to make the connection adapter specific behavior is hacky
at best, and should be re-visted once we decide how we actually want to
separate the concerns related to things that should change based on the
database adapter.

That said, this isn't something I'd expect to change based on my
database adapter. We're storing a string, so the way the database
represents a boolean should be irrelevant. It also seems strange for us
to give booleans special behavior at all in string columns. Why is
`to_s` not sufficient? It's inconsistent and confusing. Perhaps we
should consider deprecating in the future.

Fixes #17571