title: Write literal braces followed by variable in heredoc
body: <pre><code>        $js = &lt;&lt;&lt;EOS
          var data = {$jsObjectData};
  EOS;
  </code></pre>
  
  <p>results in <code>var data = ~some object data~</code></p>
  
  <p>Escaping the brace:</p>
  
  <pre><code>        $js = &lt;&lt;&lt;EOS
          var data = \{$jsObjectData};
  EOS;
  </code></pre>
  
  <p>results in <code>var data = \{~some object data~}</code></p>
  
  <p>I can't understand why does that backslash leak through it.</p>
  
  <p>Desired output: <code>var data = {~some object data~}</code></p>