Comment template for specific comment type
Enable Twig Debugging, then you'll get template suggestions printed as HTML comments directly into the markup.

I did that and got the following output:

&lt;!-- THEME DEBUG --&gt;
&lt;!-- THEME HOOK: 'comment__field_my_comment_field__article' --&gt;
&lt;!-- FILE NAME SUGGESTIONS:
   * comment--field-my-comment-field--article.html.twig
   * comment--field-my-comment-field.html.twig
   x comment.html.twig
--&gt;
&lt;!-- BEGIN OUTPUT from 'core/themes/classy/templates/content/comment.html.twig' --&gt;


So, the templates are supposed to be named like the following pattern:

comment--field-name-of-the-comment-field-in-the-content-type--content-type.html.twig
comment--field-name-of-the-comment-field-in-the-content-type.html.twig