Merge branch 'pl-feature-flag-frontend-scope' into 'master'

Avoid global feature flags for frontend too

See merge request gitlab-org/gitlab!33068

doc/development/feature_flags/development.md

@@ -87,6 +87,10 @@ this method you can expose the state of a feature flag as follows:
 
 ```ruby
 before_action do
+  # Prefer to scope it per project or user e.g.
+  push_frontend_feature_flag(:vim_bindings, project)
+
+  # Avoid, if possible
   push_frontend_feature_flag(:vim_bindings)
 end