RSpec/FeatureCategory: Refrain from marking the whole block

What does this MR do and why?

When feature_category is missing RuboCop set the whole RSpec.describe as offended node which made some IDEs like RubyMine highlight the complete file making it hard to read.

This MR ensures that only RSpec.describe ... (without do) is marked making the offenses easier on the eyes.

References

Slack (internal)

btw the feature catagory cop is annoying when using in rubymine as it highlights the whole file making it hard to see anything

yeah, i actually suggested they fix one of the files because it made the other rubocop thing impossible to see in rubymine

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Before

$ REVEAL_RUBOCOP_TODO=1 be rubocop --only RSpec/FeatureCategory ee/spec/controllers/admin/application_settings_controller_spec.rb
Inspecting 1 file
C

Offenses:

ee/spec/controllers/admin/application_settings_controller_spec.rb:5:1: C: RSpec/FeatureCategory: Please use a valid feature category. See https://docs.gitlab.com/ee/development/feature_categorization/#rspec-examples
RSpec.describe Admin::ApplicationSettingsController do ...
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

1 file inspected, 1 offense detected

After

$ REVEAL_RUBOCOP_TODO=1 be rubocop --only RSpec/FeatureCategory ee/spec/controllers/admin/application_settings_controller_spec.rb
Inspecting 1 file
C

Offenses:

ee/spec/controllers/admin/application_settings_controller_spec.rb:5:1: C: RSpec/FeatureCategory: Please use a valid feature category. See https://docs.gitlab.com/ee/development/feature_categorization/#rspec-examples
RSpec.describe Admin::ApplicationSettingsController do
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

1 file inspected, 1 offense detected

Note the diff of:

RSpec.describe Admin::ApplicationSettingsController do

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

How to set up and validate locally

1. REVEAL_RUBOCOP_TODO=1 bundle exec rubocop --only RSpec/FeatureCategory ee/spec/controllers/admin/application_settings_controller_spec.rb