message: Fix DynamicImage docs
diff: @@ -454,7 +454,7 @@ impl DynamicImage {
  }
  }
  - /// Return a reference to an 16bit RGB image
  + /// Return a reference to an 32bit RGB image
  pub fn as_rgb32f(&self) -> Option<&Rgb32FImage> {
  match *self {
  DynamicImage::ImageRgb32F(ref p) => Some(p),
  