Add RSpec. to top level class describe blocks

THis is to enforce RSpec zero monkey patching mode

doc/development/geo/framework.md

@@ -215,7 +215,7 @@ For example, to add support for files referenced by a `Widget` model with a
 
    require 'spec_helper'
 
-   describe Geo::WidgetReplicator do
+   RSpec.describe Geo::WidgetReplicator do
      let(:model_record) { build(:widget) }
 
      it_behaves_like 'a blob replicator'
@@ -301,7 +301,7 @@ For example, to add support for files referenced by a `Widget` model with a
 
    require 'spec_helper'
 
-   describe Geo::WidgetRegistry, :geo, type: :model do
+   RSpec.describe Geo::WidgetRegistry, :geo, type: :model do
      let_it_be(:registry) { create(:widget_registry) }
 
      specify 'factory is valid' do
@@ -428,7 +428,7 @@ Widgets should now be verified by Geo!
 
    require 'spec_helper'
 
-   describe Resolvers::Geo::WidgetRegistriesResolver do
+   RSpec.describe Resolvers::Geo::WidgetRegistriesResolver do
      it_behaves_like 'a Geo registries resolver', :widget_registry
    end
    ```
@@ -452,7 +452,7 @@ Widgets should now be verified by Geo!
 
    require 'spec_helper'
 
-   describe Geo::WidgetRegistryFinder do
+   RSpec.describe Geo::WidgetRegistryFinder do
      it_behaves_like 'a framework registry finder', :widget_registry
    end
    ```
@@ -484,7 +484,7 @@ Widgets should now be verified by Geo!
 
    require 'spec_helper'
 
-   describe GitlabSchema.types['WidgetRegistry'] do
+   RSpec.describe GitlabSchema.types['WidgetRegistry'] do
      it_behaves_like 'a Geo registry type'
 
      it 'has the expected fields (other than those included in RegistryType)' do

doc/development/gotchas.md

@@ -20,7 +20,7 @@ Consider the following API spec:
 ```ruby
 require 'spec_helper'
 
-describe API::Labels do
+RSpec.describe API::Labels do
   it 'creates a first label' do
     create(:label)
 
@@ -71,7 +71,7 @@ Following is the fixed API spec:
 ```ruby
 require 'spec_helper'
 
-describe API::Labels do
+RSpec.describe API::Labels do
   it 'creates a first label' do
     create(:label, title: 'foo')
 

doc/development/testing_guide/testing_migrations_guide.md

@@ -112,7 +112,7 @@ migration. You can find the complete spec in
 require 'spec_helper'
 require Rails.root.join('db', 'post_migrate', '20170526185842_migrate_pipeline_stages.rb')
 
-describe MigratePipelineStages do
+RSpec.describe MigratePipelineStages do
   # Create test data - pipeline and CI/CD jobs.
   let(:jobs) { table(:ci_builds) }
   let(:stages) { table(:ci_stages) }