Add missing test case for quoting behavior

It appears that the only time that `quote` is called with a column,
but without first calling `type_cast` is when where is called with an
array. My previous pull request broke this behavior, without failing
tests. This adds a test for the only case I can think of that exercises
the `if column.type == :integer` branch of `quote` effectively.
print generators on failed generate

Let's say we just ran:

```
$ rails g migrate add_click_to_issue_assignment
```

We will get an error that looks like:

```
Could not find generator migrate.
```

This patch adds all existing migrations to the output to make it easier for a developer to find a valid migration.

```
Could not find generator "migrate". Please select a valid generator:
Rails:
  assets
  controller
  generator
  helper
  integration_test
  mailer
  migration
  model
  resource
  scaffold
  scaffold_controller
  task
```


It would be nice to do some spelling detection and suggest alternatives, but for now this should  help.
Remove checks against `column.type` in abstract adapter quoting

The intention is to eventually remove `column` from the arguments list
both for `quote` and for `type_cast` entirely. This is the first step
to that end.
Merge pull request #15335 from sgrif/sg-missing-test-case

Add missing test case for quoting behavior
Merge pull request #15336 from sgrif/sg-quoting

Remove checks against `column.type` in abstract adapter quoting
Refactor the type casting of booleans in MySQL
Merge pull request #15339 from sgrif/sg-mysql-booleans

Refactor the type casting of booleans in MySQL
Correct Documentation for asset_tag_helpers
update the recommended ruby version
Merge pull request #15340 from aditya-kapoor/correct-docs

Correct Documentation for asset_tag_helpers
Merge pull request #15294 from schneems/schneems/generator-output-in-error2

print generators on failed generate
Merge pull request #15333 from ShunsukeAida/update_ruby_version

update the recommended ruby version.