Convert Basic to use starterkit theme

We are going to remove the field.html.twig to the default stable. Which removes this code and BEM class syntax

# Create classes array #}
{% set classes = [] %}

{# BEM inspired class syntax: https://en.bem.info/
   Enable this code if you would like field classes like "article__tags", where article is the content type and field_tags is the field name.
#}
{% set classes = classes|merge([
  bundle ~ '__' ~ field_name|replace({'field_' : ''})|clean_class
]) %}

When generating the starterkit it copied over final class StarterKit by accident it seems because that would fail as it's the same namespace.

Fixed, thanks for your help @occupant!