Remove code_navigation_references feature flag

It was enabled by default in 13.3 and no issues were seen. It's
now safe to remove the feature flag.

app/services/ci/create_job_artifacts_service.rb

@@ -22,11 +22,7 @@ module Ci
       return result unless result[:status] == :success
 
       headers = JobArtifactUploader.workhorse_authorize(has_length: false, maximum_size: max_size(artifact_type))
-
-      if lsif?(artifact_type)
-        headers[:ProcessLsif] = true
-        headers[:ProcessLsifReferences] = Feature.enabled?(:code_navigation_references, project, default_enabled: true)
-      end
+      headers[:ProcessLsif] = lsif?(artifact_type)
 
       success(headers: headers)
     end

doc/user/project/code_intelligence.md

@@ -40,38 +40,18 @@ The generated LSIF file must be less than 170MiB.
 
 After the job succeeds, code intelligence data can be viewed while browsing the code:
 
-![Code intelligence](img/code_intelligence_v13_1.png)
+![Code intelligence](img/code_intelligence_v13_4.png)
 
 ## Find references
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/217392) in GitLab 13.2.
-> - [Became enabled by default](https://gitlab.com/gitlab-org/gitlab/-/issues/225621) on GitLab 13.3.
-> - It's enabled on GitLab.com.
+> - [Feature flag removed](https://gitlab.com/gitlab-org/gitlab/-/issues/235735) in GitLab 13.4.
 
 To find where a particular object is being used, you can see links to specific lines of code
 under the **References** tab:
 
 ![Find references](img/code_intelligence_find_references_v13_3.png)
 
-### Enable or disable find references
-
-Find references is under development but ready for production use.
-It is deployed behind a feature flag that is **enabled by default**.
-[GitLab administrators with access to the GitLab Rails console](../../administration/feature_flags.md)
-can opt to disable it for your instance.
-
-To disable it:
-
-```ruby
-Feature.disable(:code_navigation_references)
-```
-
-To enable it:
-
-```ruby
-Feature.enable(:code_navigation_references)
-```
-
 ## Language support
 
 Generating an LSIF file requires a language server indexer implementation for the

spec/requests/api/ci/runner/jobs_artifacts_spec.rb

@@ -238,13 +238,6 @@ RSpec.describe API::Ci::Runner, :clean_gitlab_redis_shared_state do
             expect(json_response['ProcessLsif']).to be_truthy
           end
 
-          it 'adds ProcessLsifReferences header' do
-            authorize_artifacts_with_token_in_headers(artifact_type: :lsif)
-
-            expect(response).to have_gitlab_http_status(:ok)
-            expect(json_response['ProcessLsifReferences']).to be_truthy
-          end
-
           context 'code_navigation feature flag is disabled' do
             it 'responds with a forbidden error' do
               stub_feature_flags(code_navigation: false)
@@ -253,20 +246,6 @@ RSpec.describe API::Ci::Runner, :clean_gitlab_redis_shared_state do
               aggregate_failures do
                 expect(response).to have_gitlab_http_status(:forbidden)
                 expect(json_response['ProcessLsif']).to be_falsy
-                expect(json_response['ProcessLsifReferences']).to be_falsy
-              end
-            end
-          end
-
-          context 'code_navigation_references feature flag is disabled' do
-            it 'sets ProcessLsifReferences header to false' do
-              stub_feature_flags(code_navigation_references: false)
-              authorize_artifacts_with_token_in_headers(artifact_type: :lsif)
-
-              aggregate_failures do
-                expect(response).to have_gitlab_http_status(:ok)
-                expect(json_response['ProcessLsif']).to be_truthy
-                expect(json_response['ProcessLsifReferences']).to be_falsy
               end
             end
           end