Add Misc/NEWS entry and relevant doc change for issue 10271.
diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index 8af19a2..8387f5a 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -339,8 +339,7 @@
Write a warning to a file. The default implementation calls
``formatwarning(message, category, filename, lineno, line)`` and writes the
resulting string to *file*, which defaults to ``sys.stderr``. You may replace
- this function with an alternative implementation by assigning to
- ``warnings.showwarning``.
+ this function with any callable by assigning to ``warnings.showwarning``.
*line* is a line of source code to be included in the warning
message; if *line* is not supplied, :func:`showwarning` will
try to read the line specified by *filename* and *lineno*.