<%= content_tag_for(:span, attachment, class: "inline") do %>
  <%= link_to attachment.title, attachment.url %>
  [<%= attachment_attributes(attachment) %>]
<% end %>

<%= content_tag_for(:span, attachment, class: "inline") do %>
  <%= link_to attachment.title, attachment.url %>
  (<%= attachment_attributes(attachment) %>)
<% end %>

Update non style guide compliant square brackets for inline attachments
Update non style guide compliant square brackets for inline attachments

https://www.pivotaltracker.com/story/show/58656846
