versionadded directive and releasenotes added

docs/releasenotes/8.2.0.rst

@@ -73,6 +73,15 @@ be specified through a keyword argument::
 
     im.save("out.tif", icc_profile=...)
 
+
+ImageOps.autocontrast: tone preserving option
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The default behaviour of the :py:meth:`~PIL.ImageOps.autocontrast` is to normalize separate
+histograms for each color channel, it changes tone of the image. Added ``preserve_tone``
+argument which avoids changing the tone of the image using one luminance histogram for all
+channels.
+
 Security
 ========
 

src/PIL/ImageOps.py

@@ -78,6 +78,9 @@ def autocontrast(image, cutoff=0, ignore=None, mask=None, preserve_tone=False):
                  within the mask. If no mask is given the entire image is used
                  for histogram computation.
     :param preserve_tone: Preserve image tone in Photoshop-like style autocontrast.
+
+                          .. versionadded:: 1.1.5
+
     :return: An image.
     """
     if preserve_tone: