marktheme hook is really just a "tag" with "attributes" and a "value" (one line, more or less, template)
marktheme hook is not extensible (cannot add classes via a preprocess function, must override the template).
- Convert all invocations of
'#theme' => 'mark'to
'#type' => 'html_tag__mark'
- Move data logic from the template to a preprocess function.
- Populate the attributes array with the correct classes (based on constants currently).
- Create patch
User interface changes
Conversion of a theme hook into a different theme hook suggestion?