Follow-up to #51674.

Motivation / Background

This Pull Request has been created because if you currently create a new Rails main app with the --skip-jbuilder option, scaffolded controllers do not comply with rubocop-rails-omakase rules.

Steps to repro the issue:

• Run the following

  rails new myapp --main --skip-jbuilder; cd myapp
  rails generate scaffold post title
  bundle exec rubocop
  

• Expected behavior: there should be no Rubocop offenses
• Actual behavior: the are Rubocop offenses:

  Inspecting 31 files
  ...C...........................
  
  Offenses:
  
  app/controllers/posts_controller.rb:56:27: C: [Correctable] Layout/SpaceInsideArrayLiteralBrackets: Use space inside array brackets.
        params.expect(post: [:title])
                            ^
  app/controllers/posts_controller.rb:56:34: C: Layout/SpaceInsideArrayLiteralBrackets: Use space inside array brackets.
        params.expect(post: [:title])
                                   ^
  

Detail

This Pull Request changes the controller generators to use spaces around [ and ].

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Unrelated changes should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.