Issue #13522: Fix _Py_co_pow() documentation

Patch written by Arnaud Calmettes.
diff --git a/Doc/c-api/complex.rst b/Doc/c-api/complex.rst
index f5304bd..90e9c03 100644
--- a/Doc/c-api/complex.rst
+++ b/Doc/c-api/complex.rst
@@ -72,7 +72,7 @@
    Return the exponentiation of *num* by *exp*, using the C :ctype:`Py_complex`
    representation.
 
-   If :attr:`exp.imag` is not null, or :attr:`exp.real` is negative,
+   If *num* is null and *exp* is not a positive real number,
    this method returns zero and sets :cdata:`errno` to :cdata:`EDOM`.