Apply suggestions from code review

Co-authored-by: Victor Stinner <vstinner@python.org>

Author: sobolevn

Include/cpython/dictobject.h

@@ -107,6 +107,6 @@ PyAPI_FUNC(int) PyDict_Unwatch(int watcher_id, PyObject* dict);
 // Create a frozendict. Create an empty dictionary if iterable is NULL.
 PyAPI_FUNC(PyObject*) PyFrozenDict_New(PyObject *iterable);
 
-// Create a frozendict from existing `PyDictObject`.
+// Create a frozendict from existing dict.
 // Transfers existing keys and values.
 PyAPI_FUNC(PyObject*) PyDict_AsFrozenDictAndClear(PyObject *dict);

Lib/test/test_capi/test_dict.py

@@ -628,10 +628,10 @@ def test_dict_as_frozendict_and_clear(self):
 
         class DictSubtype(dict): ...
 
-        d = DictSubtype({'x': 123})
+        d = DictSubtype(x=123)
         f = as_frozendict(d)
         self.assertIs(type(f), frozendict)
-        self.assertEqual(f, frozendict({'x': 123}))
+        self.assertEqual(f, frozendict(x=123))
         self.assertIs(type(d), DictSubtype)
         self.assertEqual(d, DictSubtype({}))