Address feedback from Andrej

Also comments from discussion thread:
  https://discuss.python.org/t/pep-728-typeddict-with-typed-extra-items/45443/148

Author: PIG208

peps/pep-0728.rst

@@ -187,9 +187,10 @@ determining `supported and unsupported operations
 The ``extra_items`` Class Parameter
 -----------------------------------
 
-For a TypedDict type that specifies ``extra_items``, during construction, the
-value type of each unknown item is expected to be non-required and assignable
-to the ``extra_items`` argument. For example::
+By default ``extra_items`` is unset.  For a TypedDict type that specifies
+``extra_items``, during construction, the value type of each unknown item
+is expected to be non-required and assignable to the ``extra_items`` argument.
+For example::
 
     class Movie(TypedDict, extra_items=bool):
         name: str
@@ -233,15 +234,14 @@ Here, ``'year'`` in ``a`` is an extra key defined on ``Movie`` whose value type
 is ``int``. ``'other_extra_key'`` in ``b`` is another extra key whose value type
 must be assignable to the value of ``extra_items`` defined on ``MovieBase``.
 
-``extra_items`` is also supported with the functional syntax::
-
-    Movie = TypedDict("Movie", {"name": str}, extra_items=int | None)
-
 .. _typed-dict-closed:
 
 The ``closed`` Class Parameter
 ------------------------------
 
+When neither ``extra_items`` nor ``closed=True`` is specified, ``closed=False``
+is assumed.
+
 When ``closed=True`` is set, no extra items are allowed. This is equivalent to
 ``extra_items=Never``, because there can't be a value type that is assignable to
 :class:`~typing.Never`. It is a runtime error to use the ``closed`` and
@@ -275,8 +275,11 @@ child class is also closed::
 
 As a consequence of ``closed=True`` being equivalent to ``extra_items=Never``,
 the same rules that apply to ``extra_items=Never`` also apply to
-``closed=True``. It is possible to use ``closed=True`` when subclassing if the
-``extra_items`` argument is a read-only type::
+``closed=True``. While they both have the same effect, ``closed=True`` is
+preferred over ``extra_items=Never``.
+
+It is possible to use ``closed=True`` when subclassing if the ``extra_items``
+argument is a read-only type::
 
     class Movie(TypedDict, extra_items=ReadOnly[str]):
         pass
@@ -290,8 +293,7 @@ the same rules that apply to ``extra_items=Never`` also apply to
 This will be further discussed in
 :ref:`a later section <pep728-inheritance-read-only>`.
 
-When neither ``extra_items`` nor ``closed=True`` is specified, ``closed=False``
-is assumed. The TypedDict should allow non-required extra items of value type
+The TypedDict should allow non-required extra items of value type
 ``ReadOnly[object]`` during inheritance or assignability checks, to
 preserve the default TypedDict behavior. Extra keys included in TypedDict
 object construction should still be caught, as mentioned in TypedDict's
@@ -770,7 +772,7 @@ where ``closed=True`` is required for ``__extra_items__`` to be treated
 specially, to avoid key collision.
 
 Some members of the community concern about the elegance of the syntax.
-Practiaclly, the key collision with a regular key can be mitigated with
+Practically, the key collision with a regular key can be mitigated with
 workarounds, but since using a reserved key is central to this proposal,
 there are limited ways forward to address the concerns.