[3.7] Fix misleading mentions of tp_size in comments. (GH-9136)

Many type object initializations labeled a field "tp_size" in the
comment, but the name of that field is tp_basicsize..
(cherry picked from commit 0e0bc4e221f592f305d335faf5f8046484eb9238)

Co-authored-by: Peter Eisentraut <peter@eisentraut.org>
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index 8fb368e..c4bf081 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -35,7 +35,7 @@
 PyTypeObject PyModuleDef_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "moduledef",                                /* tp_name */
-    sizeof(struct PyModuleDef),                 /* tp_size */
+    sizeof(struct PyModuleDef),                 /* tp_basicsize */
     0,                                          /* tp_itemsize */
 };
 
@@ -789,7 +789,7 @@
 PyTypeObject PyModule_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "module",                                   /* tp_name */
-    sizeof(PyModuleObject),                     /* tp_size */
+    sizeof(PyModuleObject),                     /* tp_basicsize */
     0,                                          /* tp_itemsize */
     (destructor)module_dealloc,                 /* tp_dealloc */
     0,                                          /* tp_print */