title: Multi-line string in Rust with preserved leading whitespace
body: <p>In some languages it is possible to write something of this sort:</p>
  
  <pre><code>val some_string =
    """First line.
      | Second line, with leading space."""
  </code></pre>
  
  <p>That is, a multi-line string where all leading space is removed up to a point, but no further. This can be mimicked in Rust by writing:</p>
  
  <pre><code>let some_string = 
      "First line.\n \
       Second line, with leading space.";
  </code></pre>
  
  <p>However, this loses the benefit of looking closer to the actual output. Is there a way in Rust of writing something like the example pseudocode, preserving (some) leading whitespace?</p>