bpo-45459: Fix PyModuleDef_Slot type in the limited C API (GH-31668)

Move the type definition to pytypedefs.h.

Author: vstinner

Include/moduleobject.h

@@ -55,14 +55,12 @@ typedef struct PyModuleDef_Base {
     NULL, /* m_copy */          \
   }
 
-struct PyModuleDef_Slot;
-
 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03050000
 /* New in 3.5 */
-typedef struct PyModuleDef_Slot{
+struct PyModuleDef_Slot {
     int slot;
     void *value;
-} PyModuleDef_Slot;
+};
 
 #define Py_mod_create 1
 #define Py_mod_exec 2

Include/pytypedefs.h

@@ -10,6 +10,7 @@ extern "C" {
 #endif
 
 typedef struct PyModuleDef PyModuleDef;
+typedef struct PyModuleDef_Slot PyModuleDef_Slot;
 typedef struct PyMethodDef PyMethodDef;
 typedef struct PyGetSetDef PyGetSetDef;
 typedef struct PyMemberDef PyMemberDef;