Cleanup highlight_js_worker feature flag

app/assets/javascripts/pages/projects/blob/show/index.js

...javascripts/repository/components/blob_content_viewer.vue

...s/javascripts/repository/components/blob_viewers/index.js

app/assets/javascripts/repository/index.js

app/assets/javascripts/repository/mixins/highlight_mixin.js

...pts/vue_shared/components/source_viewer/source_viewer.vue

...vue_shared/components/source_viewer/source_viewer_new.vue

app/controllers/projects/blob_controller.rb

app/controllers/projects/tree_controller.rb

app/controllers/projects_controller.rb

config/feature_flags/development/highlight_js_worker.yml

doc/user/project/repository/git_blame.md

...rontend/repository/components/blob_content_viewer_spec.js

...rontend/repository/components/blob_content_viewer_spec.js

spec/frontend/repository/mixins/highlight_mixin_spec.js

...shared/components/source_viewer/source_viewer_new_spec.js

...vue_shared/components/source_viewer/source_viewer_spec.js