address review: suggest PyComplex_AsCComplex/PyComplex_FromCComplex

Author: skirpichev

Doc/deprecations/c-api-pending-removal-in-3.20.rst

@@ -1,4 +1,7 @@
 Pending removal in Python 3.20
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-* The ``cval`` field in :c:type:`PyComplexObject` (:gh:`128813`).
+* The ``cval`` field in :c:type:`PyComplexObject` (:gh:`128813`):
+  Use :c:func:`PyComplex_AsCComplex` and :c:func:`PyComplex_FromCComplex`
+  to convert a Python complex number to/from the C :c:type:`Py_complex`
+  representation.

Doc/whatsnew/3.15.rst

@@ -571,7 +571,10 @@ Deprecated C APIs
   (Contributed by Serhiy Storchaka in :gh:`132629`.)
 
 * Deprecate :c:member:`~PyComplexObject.cval` field of the the
-  :c:type:`PyComplexObject` type.
+  :c:type:`PyComplexObject` type:
+  Use :c:func:`PyComplex_AsCComplex` and :c:func:`PyComplex_FromCComplex`
+  to convert a Python complex number to/from the C :c:type:`Py_complex`
+  representation.
   (Contributed by Sergey B Kirpichev in :gh:`128813`.)
 
 * Functions :c:func:`_Py_c_sum`, :c:func:`_Py_c_diff`, :c:func:`_Py_c_neg`,