Add Missing ActiveSupport::Rescuable to ActionCable::Channel

[timthez, Ilia Kasianenko]

 Remove redundant suffixes on generated system tests.

Add ActiveRecord::Base.connected_to?

Make `deprecate` work for non-exists methods

This can be used to check the currently connected role. It's meant to
mirror AR::Base.connected_to

BEGIN transaction would cause COMMIT or ROLLBACK, so unless COMMIT and
ROLLBACK aren't treated as write queries as well as BEGIN, the
`ReadOnlyError` would be raised.

Prepend module in ActiveStorage overview

[ci skip]

Fix typos in click test descriptions [ci skip]

Upgrade Rubocop to 0.61.1 and fix offenses

Otherwise `save` method would raise the `ReadOnlyError` against `BEGIN`
and `ROLLBACK` queries.

Without this change, mysql2 adapter with prepared statements won't pass
`base_test.rb`.

```
% ARCONN=mysql2 be ruby -w -Itest test/cases/base_test.rb
Using mysql2
Run options: --seed 27614

# Running:

....S..............................F

Failure:
BasicsTest#test_creating_a_record_raises_if_preventing_writes [test/cases/base_test.rb:1493]:
ActiveRecord::ReadOnlyError expected but nothing was raised.

rails test test/cases/base_test.rb:1492

...F

Failure:
BasicsTest#test_deleting_a_record_raises_if_preventing_writes [test/cases/base_test.rb:1513]:
ActiveRecord::ReadOnlyError expected but nothing was raised.

rails test test/cases/base_test.rb:1510

............................................................................................................F

Failure:
BasicsTest#test_updating_a_record_raises_if_preventing_writes [test/cases/base_test.rb:1503]:
ActiveRecord::ReadOnlyError expected but nothing was raised.

rails test test/cases/base_test.rb:1500

..........

Finished in 2.534490s, 62.7345 runs/s, 149.5370 assertions/s.
159 runs, 379 assertions, 3 failures, 0 errors, 1 skips
```

Follow up #34505.

Because `skip-javascript` option is specified for the dummy application
used in the integration tests.
https://github.com/rails/rails/blob/bdc96802a7a4a8c6d183272e997430e8b9006498/activejob/test/support/integration/helper.rb#L14

Rename error that occurs when writing on a read

* `#create_or_find_by/!`: add more tests

* Fix docs of `create_or_find_by`

This method uses `find_by!` internally.

Fix typo in per-form CSRF token docs [ci skip]

I originally named this `StatementInvalid` because that's what we do in
GitHub, but `@tenderlove` pointed out that this means apps can't test
for or explitly rescue this error. `StatementInvalid` is pretty broad so
I've renamed this to `ReadOnlyError`.

Move type method inside ActionDispatch::Journey::Nodes::Symbol

Before #33325, `deprecate` works for non-exist methods.
This is necessary, for example, if want to deprecate dynamically defined
methods like attributes methods.

Fixes #34646

This first started with moving type method inside
`ActionDispatch::Journey::Nodes::Symbol`.

`AD::Journey::Nodes::Symbol#type` was generated dynamically with an
`each` block. While this is OK for classes like `AD::Journey::Nodes::Slash`
or `AD::Journey::Nodes::Dot` which don't have further implementation, all
other classes containing more logic have this method defined in their class
body. This patch does the same in this case.

On code review process @kamipo suggested to fully expand over
metaprogramming for Slash and Dot classes, a topic on which I agree with him.

* No need to go through ruby

* Abort early if a generator command fails

* Reuse `rails_command` method

* Bump thor minimum dependency to 0.20.3

* Add some minimal docs

* Add a changelog entry

* Restore original logging

Prevent non-primary mouse button clicks from triggering click events

Stop trying to reconnect on unauthorized cable connections

And make sure new applications in Rails 6.0 has this config enabled.

Also, improve test coverage and add a CHANGELOG entry.

Fix join table column quoting with SQLite.

Make AJ::Base#enqueue return false if the job wasn't enqueued

Update bundler to 2.0.0.pre.2

Add MailDeliveryJob for unified mail delivery