rubocop: Add types for extractors

[tk0miya]

Add types to RuboCop::Runner.ruby_extractors and related modules.

[github-actions]

@tk0miya Thanks for your contribution!

Please follow the instructions below for each change.
See also: https://github.com/ruby/gem_rbs_collection/blob/main/docs/CONTRIBUTING.md

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---

rubocop-ast

You changed RBS files for an existing gem.
You need to get approval from the reviewers of this gem.

@kozy4324, please review this pull request.
If this change is acceptable, please make a review comment including APPROVE from here.

After that, the PR author or the reviewers can merge this PR.
Just comment /merge to merge this PR.

---

rubocop

You changed RBS files for an existing gem.
You need to get approval from the reviewers of this gem.

@kozy4324, please review this pull request.
If this change is acceptable, please make a review comment including APPROVE from here.

After that, the PR author or the reviewers can merge this PR.
Just comment /merge to merge this PR.

[kozy4324]

APPROVE

[github-actions]

Thanks for your review, @kozy4324!

@tk0miya, @kozy4324 This PR is ready to be merged.
Just comment /merge to merge this PR.

[kozy4324]

/merge

[tk0miya]

Thank you for reviewing!