title: Change standard error color for geom_smooth
body: <p>I'm plotting some data using geom_smooth and looking for a way to change the color of the standard error shading for each line to match that line (ie., a red line would have it's standard error shaded red).</p>
  
  <p>I've looked through the official ggplot2 documentation as well as the list of opts() at <a href="https://github.com/hadley/ggplot2/wiki/%2Bopts%28%29-List" rel="noreferrer">https://github.com/hadley/ggplot2/wiki/%2Bopts%28%29-List</a>.</p>
  
  <p>Any advice (or just confirmation of whether or not it's possible) is appreciated.</p>