Fix Layout/CommentIndentation for comment-only pattern matching

[nekketsuuu]

I'd like to allow the following code which uses pattern matching:

case instruction
in :nop
  # do nothing
in :inc
  ret += 1
end

Before this patch, the indentation of "do nothing" comment is corrected to the same indent level as that of in, which is inconsistent with the indentation rule of case ... when ... end.

$ ruby --version
ruby 3.3.1 (2024-04-23 revision c56cd86388) [x86_64-linux]
$ bundle show rubocop
/home/nek/.rbenv/versions/3.3.1/lib/ruby/gems/3.3.0/gems/rubocop-1.63.4
$ cat test.rb
case instruction
in :nop
  # do nothing
in :inc
  ret += 1
end
$ bundle exec rubocop test.rb --only Layout/CommentIndentation
Inspecting 1 file
C

Offenses:

test.rb:3:3: C: [Correctable] Layout/CommentIndentation: Incorrect indentation detected (column 2 instead of 0).
  # do nothing
  ^^^^^^^^^^^^

1 file inspected, 1 offense detected, 1 offense autocorrectable

---

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[koic]

Thanks!