Change which template is served in a Twenty Twenty-One child theme to incorporate wporg-developer

wporg-developer-get-template-part.php

<?php

//In single.php of twentytwentyone theme, find this line

get_template_part( 'template-parts/content/content-single' );

//and replace it with this condition to blend the code reference features of the wporg-developer theme

if( DevHub\is_parsed_post_type() )
{ 
	get_template_part( 'content', 'reference' );
}
else
{
	get_template_part( 'template-parts/content/content-single' );
}

//learn more https://coreysalzano.com/wordpress/mimic-the-wordpress-org-developer-reference/