message: Fix pixels_mut/enumerate_pixels_mut comments
diff: @@ -303,8 +303,6 @@ where P: Pixel + 'static,
  Container: Deref<Target=[P::Subpixel]> + DerefMut {
  /// Returns an iterator over the mutable pixels of this image.
  - /// The iterator yields the coordinates of each pixel
  - /// along with a mutable reference to them.
  pub fn pixels_mut(&mut self) -> PixelsMut<P> {
  PixelsMut {
  chunks: self.data.chunks_mut(
  @@ -314,6 +312,8 @@ where P: Pixel + 'static,
  }
  /// Enumerates over the pixels of the image.
  + /// The iterator yields the coordinates of each pixel
  + /// along with a mutable reference to them.
  pub fn enumerate_pixels_mut(&mut self) -> EnumeratePixelsMut<P> {
  let width = self.width;
  EnumeratePixelsMut {
  