title: Why is the 'scale' argument not being applied in my dollar_format() function
body: <p>I would be grateful if anyone could explain why the scale argument is not being applied in my dollar_format function.</p>
  
  <p>usd_to_euro(100) returns the correct suffix but it remains 100 not 85.</p>
  
  <pre><code>library(scales)
  
  usd_to_euro &lt;- dollar_format(prefix = "", suffix = "\u20ac", scale = .85)
  
  usd_to_euro(100)
  </code></pre>