Add note to Railtie docs to use unique filenames

The fact that the names need to be globally unique was not obvious to me, so I
thought it'd be worth documenting. This not being clear was the cause of both
ctran/annotate_models#468 and instructure/outrigger#1.

[ci skip]

Drop IRB out of the web-console Gemfile comment

We don't provide exactly the same experience as IRB does, so let's not
advertize it like that. We can say that it's an interactive console,
without further references. I have also followed byebug's comment and
changed the calling `console` part. Hopefully, this can hint that the
invocation is not view specific and you can use it like the debugger
statement.

[ci skip]

Fix `Message::Encryptor` default cipher [ci skip]

Follow up of #29263

[ Assain Jaleel & Kasper Timm Hansen ]

Default Message Encryptor Cipher to AES-256-GCM From AES-256-CBC

- Introduce a method to select default cipher, and maintain backward compatibility

Generate field ids in `collection_check_boxes` and `collection_radio_buttons`

Document Module#delegate_missing_to in the guides [ci skip]

Added a small section for it in the `Active Support Core Extensions`
guide. [ci skip]

Fix the mistake of not using Ruby's ENV hash from the get go and get
windows support.

This makes sure that the labels are linked up with the fields.
Fixes #29014

No need to pass `#cleanup` options through to `LocalCache#clear`.

Fixes #29081. References #25628.

See https://github.com/rails/rails/issues/29067#issuecomment-301342084
for rationale.

This reverts commit b76f82d7.

Fixes #29067. Fixes #29081.

Remove `null_allowed` option from doc [ci skip]

This option was added in b9fa3541. But it does not seem to work.

Split up the caching tests as prep for adding a new cache store. Slices
the mega test/caching_test.rb into behavior modules, concrete store
tests, and cross-cutting store tests.

Considering moving cache store behavior modules into lib/ so they may be
used for acceptance testing by third parties.

[ci skip] Add backquote to :counter_cache option

Ensure MSSQL password uses real ENV var.

[ci skip] Fix another link in active_record_postgresql.md

Fix link in active_record_postgresql.md [ci skip]

remove the extra comma in association_basics.md [ci skip]

That won't be true for Action Pack and Action Mailer.

Bundle capybara 2.14.1 that includes fix for Ruby warnings

Ref: https://github.com/teamcapybara/capybara/pull/1868

Remove unreachable code

`Time.find_zone!` raise `ArgumentError` if invalid value is specified.
https://github.com/rails/rails/blob/379a0b42daf0d8e14130db7fd886d05d8d88e3f2/activesupport/lib/active_support/core_ext/time/zones.rb#L97..L99

Therefore, the return value never becomes nil.

form_with requires people to pass an id manually, so users can just
prefix their namespace right there.