Include bad and good examples to rubocop description

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What does this MR do and why?

Added good and bad examples for rubocop description files:

• rubocop/cop/rspec/httparty_basic_auth.rb
• rubocop/cop/rspec/modify_sidekiq_middleware.rb
• rubocop/cop/rspec/top_level_describe_path.rb

References

Issue: #549094

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Before	After

How to set up and validate locally

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