Fix a false positive for Layout/DefEndAlignment

[koic]

This PR fixes a false positive for Layout/DefEndAlignment when using refinements and private def.
It prevents the following error when auto-correcting.

% cat example.rb
using Module.new {
  refine Hash do
    class << Hash
      private def _ruby2_keywords_hash(*args)
      end
    end
  end
}

% bundle exec rubocop -a --only Layout/DefEndAlignment example.rb
(snip)

Inspecting 1 file
W

Offenses:

example.rb:5:7: W: [Corrected] Layout/DefEndAlignment: end at 5, 6 is
not aligned with using Module.new {
  refine Hash do
    class << Hash
      private def at 1, 0.
      end
      ^^^

0 files inspected, 1 offense detected, 1 offense corrected
Infinite loop detected in
/Users/koic/src/github.com/koic/rubocop-issues/rails/example.rb.
/Users/koic/src/github.com/rubocop-hq/rubocop/lib/rubocop/runner.rb:289:in
`check_for_infinite_loop'
/Users/koic/src/github.com/rubocop-hq/rubocop/lib/rubocop/runner.rb:272:in
`block in iterate_until_no_changes'
/Users/koic/src/github.com/rubocop-hq/rubocop/lib/rubocop/runner.rb:271:in
`loop'
/Users/koic/src/github.com/rubocop-hq/rubocop/lib/rubocop/runner.rb:271:in
`iterate_until_no_changes'
/Users/koic/src/github.com/rubocop-hq/rubocop/lib/rubocop/runner.rb:242:in
`do_inspection_loop'

I found it with the following code.
https://github.com/rails/rails/blob/v6.0.3.2/activejob/lib/active_job/arguments.rb#L73-L96

---

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• 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!