Fix RuboCop checks.

Library/.rubocop.yml

Library/Homebrew/.rubocop.yml

Library/Homebrew/cask/cask.rb

Library/Homebrew/cask/cask_loader.rb

Library/Homebrew/cask/cmd.rb

Library/Homebrew/cask/cmd/doctor.rb

Library/Homebrew/cask/cmd/info.rb

Library/Homebrew/cask/cmd/outdated.rb

Library/Homebrew/cask/cmd/upgrade.rb

Library/Homebrew/cask/dsl.rb

Library/Homebrew/cask/dsl/base.rb

Library/Homebrew/cask/exceptions.rb

Library/Homebrew/cask/utils.rb

Library/Homebrew/caveats.rb

Library/Homebrew/cleaner.rb

Library/Homebrew/cleanup.rb

Library/Homebrew/cli/args.rb

Library/Homebrew/cli/named_args.rb

Library/Homebrew/cmd/deps.rb

Library/Homebrew/cmd/doctor.rb