Fields menu item is present in two locations

It turns out this is a remnant from the content model fields View. I have fixed it with this commit, however it will not remove if from existing installs that use config sync, becuase their config will beat out the install config from this module.

To fix on a previous install

1. Go to the Views admin for the View content_model_documentation_fields (/admin/structure/views/view/content_model_fields)
2. Click on the link after "Menu:" Normal: Fields
3. In the overlay change "Type: to "No menu entry"
4. Click "Apply"
5. Save the View
6. Export your config if it is part of your site's workflow