.t.e.s.t RHTML delimiters
Sample from http://www.ruby-doc.org/stdlib/libdoc/erb/rdoc/classes/ERB.html:

   From:  James Edward Gray II <james@grayproductions.net>
    To:  <%= to %>
    Subject:  Addressing Needs

    <%= to[/\w+/] %>:

    Just wanted to send a quick note assuring that your needs are being
    addressed.

    I want you to know that my team will keep working on the issues,
    especially:

    <%# ignore numerous minor requests -- focus on priorities %>
    % priorities.each do |priority|
      
      * <%= priority %>
    % end

    Thanks for your patience.

    James Edward Gray II

Some other cases to check:

  Lines containing % should not be treated as Ruby
  %% this is a normal line, not a Ruby line
  <%% double_percents_should_be_cancelled %%>
  <% normal %>
  <%= normalexpr %>
  <%# comment %>
  <%%>
  <%=%>
  html
  <div></div>
.e.o.f.
