Documentation gaps

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### Preconditions

1. PHP 7.4.14
2. Magento 2.4-develop
3. selenium-server-standalone: stable 3.141.59
4. MacOS Catalina

### Steps to reproduce

1. Follow the MFTF setup instructions all the way up to the section https://devdocs.magento.com/mftf/docs/getting-started.html#run-tests
2. Run the tests with vendor/bin/codecept run functional -c dev/tests/acceptance/codeception.yml

### Expected result

1. Successfully run the tests
2. The documentation should explain what this region refers to

### Actual result

```
Codeception PHP Testing Framework v4.1.17
Powered by PHPUnit 9.1.5 by Sebastian Bergmann and contributors.

In ClientResolver.php line 383:

Invalid configuration value provided for "region". Expected string, but got bool(false)

region: (string)

Region to connect to. See
http://docs.aws.amazon.com/general/latest/gr/rande.html for a list of
available regions.

run [-o|--override OVERRIDE] [-e|--ext EXT] [--report] [--html [HTML]] [--xml [XML]] [--phpunit-xml [PHPUNIT-XML]] [--tap [TAP]] [--json [JSON]] [--colors] [--no-colors] [--silent] [--steps] [-d|--debug] [--bootstrap [BOOTSTRAP]] [--no-redirect] [--coverage [COVERAGE]] [--coverage-html [COVERAGE-HTML]] [--coverage-xml [COVERAGE-XML]] [--coverage-text [COVERAGE-TEXT]] [--coverage-crap4j [COVERAGE-CRAP4J]] [--coverage-cobertura [COVERAGE-COBERTURA]] [--coverage-phpunit [COVERAGE-PHPUNIT]] [--no-exit] [-g|--group GROUP] [-s|--skip SKIP] [-x|--skip-group SKIP-GROUP] [--env ENV] [-f|--fail-fast] [--no-rebuild] [--seed SEED] [--no-artifacts] [--] [ []]
```

### Notes

In the file under dev/tests/acceptance/.env, I have the following:
```
MAGENTO_BASE_URL=http://mftf.loc/
MAGENTO_BACKEND_NAME=admin
MAGENTO_ADMIN_USERNAME=xxxx
MAGENTO_ADMIN_PASSWORD=xxxxxxxxxx
SELENIUM_CLOSE_ALL_SESSIONS=true
BROWSER=chrome
MODULE_ALLOWLIST=Magento_Framework,ConfigurableProductWishlist,ConfigurableProductCatalogSearch
BROWSER_LOG_BLOCKLIST=other
ELASTICSEARCH_VERSION=7
```

In the file under dev/tests/acceptance/.credentials, I have the same entries as in .credentials.example

Start with the MFTF setup instructions at devdocs.magento.com/mftf/docs/getting-started.html#run-tests and compare them with dev/tests/acceptance/.env and .credentials.example. Reproduce the failure with vendor/bin/codecept run functional -c dev/tests/acceptance/codeception.yml; done means the documentation explains the region setting and the documented setup can run the tests successfully.

Written by the indexing model from the issue text.