Mention colour control in docs for doctest, traceback and unittest

Doc/library/doctest.rst

@@ -136,6 +136,10 @@ examples of doctests in the standard Python test suite and libraries.
 Especially useful examples can be found in the standard test file
 :file:`Lib/test/test_doctest/test_doctest.py`.
 
+.. versionadded:: 3.13
+   Output is colorized by default and can be
+   :ref:`controlled using environment variables <using-on-controlling-color>`.
+
 
 .. _doctest-simple-testmod:
 

Doc/library/traceback.rst

@@ -44,6 +44,10 @@ The module's API can be divided into two parts:
   necessary for later formatting without holding references to actual exception
   and traceback objects.
 
+.. versionadded:: 3.13
+   Output is colorized by default and can be
+   :ref:`controlled using environment variables <using-on-controlling-color>`.
+
 
 Module-Level Functions
 ----------------------

Doc/library/unittest.rst

@@ -46,9 +46,6 @@ test runner
    a textual interface, or return a special value to indicate the results of
    executing the tests.
 
-Output is in color by default and can be
-:ref:`controlled using environment variables <using-on-controlling-color>`.
-
 .. seealso::
 
    Module :mod:`doctest`
@@ -200,6 +197,9 @@ For a list of all the command-line options::
    In earlier versions it was only possible to run individual test methods and
    not modules or classes.
 
+.. versionadded:: 3.14
+   Output is colorized by default and can be
+   :ref:`controlled using environment variables <using-on-controlling-color>`.
 
 Command-line options
 ~~~~~~~~~~~~~~~~~~~~