Extend theme suggestions

For an extra field named "node_title" on the "article" content type, this is the suggestions list with the merge request:

<!-- FILE NAME SUGGESTIONS:
   * entity-extra-field--node--article--node-title--full.html.twig
   x entity-extra-field--node--article--node-title.html.twig
   * entity-extra-field--node--article.html.twig
   * entity-extra-field--article--node-title--full.html.twig
   * entity-extra-field--article--node-title.html.twig
   * entity-extra-field--article.html.twig
   * entity-extra-field--node-title.html.twig
   * entity-extra-field.html.twig
-->

Great @damienmckenna look full-featured now! :)
It also looks like old suggestions are preserved, if I'm not missing anything. I guess you also checked that? (BC)