Issue #15497: Correct characters in TextWrapper.replace_whitespace docs.

Patch by Chris Jerdonek.

diff --cc Doc/library/textwrap.rst
index 50c710c522e4e840e467405f986b0edae6c8edb6,547db79d77c15edfcebdec6bf152144f7187b60f..0ac1cc60786f8167d7ace0f15f0e0be769bd3cc1
--- 1/Doc/library/textwrap.rst
--- 2/Doc/library/textwrap.rst
+++ b/Doc/library/textwrap.rst
@@@ -134,20 -107,13 +134,22 @@@ in a block of text
        expanded to spaces using the :meth:`expandtabs` method of *text*.
  
  
 +   .. attribute:: tabsize
 +
 +      (default: ``8``) If :attr:`expand_tabs` is true, then all tab characters
 +      in *text* will be expanded to zero or more spaces, depending on the
 +      current column and the given tab size.
 +
 +      .. versionadded:: 3.3
 +
 +
     .. attribute:: replace_whitespace
  
-       (default: ``True``) If true, each whitespace character (as defined by
-       ``string.whitespace``) remaining after tab expansion will be replaced by a
-       single space.
+       (default: ``True``) If true, after tab expansion but before wrapping,
+       the :meth:`wrap` method will replace each whitespace character
+       with a single space.  The whitespace characters replaced are
+       as follows: tab, newline, vertical tab, formfeed, and carriage
+       return (``'\t\n\v\f\r'``).
  
        .. note::