Some routes can use a shorter version of a helper.
That allows skipping a namespace object.

The two following helpers produce the same result.

```
app.namespace_project_error_tracking_projects_path(
  @project.namespace, @project
)

app.project_error_tracking_projects_path(
  @project
)
```

More info here
https://gitlab.com/gitlab-org/gitlab
/-/blob/v12.5.0-ee/config/application.rb#L279-291