Support Nokogiri::HTML.parse and Nokogiri::HTML5.parse on Rails/ResponseParsedBody

[r7kamura]

Since Rails 7.1, response.parse_body now supports Content-Type: text/html responses:

• ActionDispatch::Testing::TestResponse#parsed_body parse HTML with Nokogiri rails/rails#47144

So, how about adding support for this in the Rails/ResponseParsedBody cop?

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Before submitting the PR make sure the following are checked:

• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• 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.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.
• If this is a new cop, consider making a corresponding update to the Rails Style Guide.

[koic]

I've left a few review comments, please integrate html5 into html.

[r7kamura]

Thanks for reviewing. It certainly has improved as the HTML and HTML5 logics has been put together 👍