At this point in the T377978 story, it is possible to favourite a template when searching for it in the initial template-search form. This task is to also add a favourite button to the template editing form that is used both just after selecting a new template and also when clicking the edit button on a template that's already in a wiki page.
This task is only for adding this to TemplateWizard; see T385845 for the equivalent for adding to VisualEditor.
The button should go next to the 'close' and 'link' buttons.