Remove PEP reference from header

Author: encukou

peps/pep-0803.rst

@@ -161,8 +161,8 @@ they will not yet be removed from the Limited API:
 - :c:func:`PyModule_FromDefAndSpec`, :c:func:`PyModule_FromDefAndSpec2`
 
 
-New Export Hook (:pep:`793`)
-----------------------------
+New Export Hook (PEP 793)
+-------------------------
 
 Implementation of this PEP requires :pep:`793` (``PyModExport``:
 A new entry  point for C extension modules) to be