pythongh-121249: Note struct module changes in What's New (python#131867)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: skirpichev

Doc/whatsnew/3.14.rst

@@ -904,6 +904,15 @@ ssl
   (Contributed by Will Childs-Klein in :gh:`128036`.)
 
 
+struct
+------
+
+* Support the :c:expr:`float complex` and :c:expr:`double complex` C types in
+  the :mod:`struct` module (formatting characters ``'E'`` and ``'C'``,
+  respectively) if the compiler has C11 complex arithmetic.
+  (Contributed by Sergey B Kirpichev in :gh:`121249`.)
+
+
 symtable
 --------