gh-115119: defer removal of bundled libmpdec to 3.16

Doc/deprecations/c-api-pending-removal-in-3.15.rst

@@ -1,7 +1,6 @@
 Pending removal in Python 3.15
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-* The bundled copy of ``libmpdecimal``.
 * The :c:func:`!PyImport_ImportModuleNoBlock`:
   Use :c:func:`PyImport_ImportModule` instead.
 * :c:func:`PyWeakref_GetObject` and :c:func:`PyWeakref_GET_OBJECT`:

Doc/deprecations/c-api-pending-removal-in-3.16.rst

@@ -0,0 +1,4 @@
+Pending removal in Python 3.16
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* The bundled copy of ``libmpdecimal``.

Doc/whatsnew/3.13.rst

@@ -2577,7 +2577,7 @@ Build Changes
 
 * The :file:`configure` option :option:`--with-system-libmpdec`
   now defaults to ``yes``.
-  The bundled copy of ``libmpdecimal`` will be removed in Python 3.15.
+  The bundled copy of ``libmpdecimal`` will be removed in Python 3.16.
 
 * Python built with :file:`configure` :option:`--with-trace-refs`
   (tracing references) is now ABI compatible with the Python release build