<h3>Parent</h3>

<%= f.select :parent,
    options_for_select(TagFetcher.new.tags_of_type('topic'), @tagging_update.parent),
    { include_blank: true },
    { multiple: false, class: "select2", data: { placeholder: "Choose a parent (topic)..." } } %>

<h3>Parent</h3>

<%= f.select :parent,
    options_for_select(TagFetcher.new.tags_of_type('mainstream_browse_page'), @tagging_update.parent),
    { include_blank: true },
    { multiple: false, class: "select2", data: { placeholder: "Choose a parent (topic)..." } } %>

Fix kind of content available for 'parent'
Fix kind of content available for 'parent'

The "parent" tag is the primary mainstream browse pages, so the select
box should be populated with those, not the topics.
