[Fix #8252] Fix a typo for --safe-auto-correct command line option

[koic]

Fixes #8252.

This PR fixes a command line option name from --safe-autocorrect to --safe-auto-correct, which is compatible with RuboCop 0.66 and lower.

Before:

% bundle exec ./exe/rubocop --safe-auto-correct
invalid option: --safe-auto-correct
Did you mean?  safe-autocorrect
For usage information, use --help

After:

% bundle exec ./exe/rubocop --safe-auto-correct
--safe-auto-correct is deprecated; use --auto-correct
Inspecting 1082 files

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.

[bbatsov]

Thanks!