gh-134567: Move unittest What’s New entry (#136630)

Author: garry-cairns

Doc/whatsnew/3.15.rst

@@ -278,6 +278,14 @@ tarfile
   and :cve:`2025-4435`.)
 
 
+unittest
+--------
+
+* :func:`unittest.TestCase.assertLogs` will now accept a formatter
+  to control how messages are formatted.
+  (Contributed by Garry Cairns in :gh:`134567`.)
+
+
 zlib
 ----
 
@@ -388,15 +396,6 @@ typing
   (Contributed by Bénédikt Tran in :gh:`133823`.)
 
 
-unittest
---------
-
-* Lets users specify formatter in TestCase.assertLogs.
-  :func:`unittest.TestCase.assertLogs` will now accept a formatter
-  to control how messages are formatted.
-  (Contributed by Garry Cairns in :gh:`134567`.)
-
-
 wave
 ----