title: How to use ruamel.yaml to dump literal scalars
body: <p>I've searched and found "similar" posts, but nothing that answers my question directly. I also found  a <a href="https://stackoverflow.com/questions/35433838/how-to-dump-a-folded-scalar-to-yaml-in-python-using-ruamel">stackoverflow post here</a>, but no answers.</p>
  
  <p>I need to write to a <code>yaml</code> file using the following format:</p>
  
  <pre><code>any_value: 123.4
  data_points: |-
    0.0, 1.0
    0.1, 1.5
    0.2, 1.7
  </code></pre>
  
  <p>If I use a long string containing <code>\n</code> in it, it will just print it as-is:</p>
  
  <pre><code>any_value: 123.4
  data_points: "0.0, 1.0\n0.1, 1.5\n0.2, 1.7"
  </code></pre>
  
  <p>Which is not what I want. I can also pass it as a list where each item looks like this</p>
  
  <pre><code>['0.0, 1.0', '0.1, 1.5', '0.2, 1.7']
  </code></pre>
  
  <p>But that only results in</p>
  
  <pre><code>any_value: 123.4
  data_points:
  - 0.0, 1.0
  - 0.1, 1.5
  - 0.2, 1.7
  </code></pre>
  
  <p>It kinda looks like the first one, but it isn't. How do I get ruamel.yaml to dump it the way I want?</p>