[3.14] gh-141004: Document C APIs for dictionary keys, values, and items (GH-141009) (GH-141512)

gh-141004: Document C APIs for dictionary keys, values, and items (GH-141009)
(cherry picked from commit f72768f30e)

Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Petr Viktorin <encukou@gmail.com>

Doc/c-api/dict.rst

@@ -431,3 +431,49 @@ Dictionary Objects
    it before returning.
 
    .. versionadded:: 3.12
+
+
+Dictionary View Objects
+^^^^^^^^^^^^^^^^^^^^^^^
+
+.. c:function:: int PyDictViewSet_Check(PyObject *op)
+
+   Return true if *op* is a view of a set inside a dictionary. This is currently
+   equivalent to :c:expr:`PyDictKeys_Check(op) || PyDictItems_Check(op)`. This
+   function always succeeds.
+
+
+.. c:var:: PyTypeObject PyDictKeys_Type
+
+   Type object for a view of dictionary keys. In Python, this is the type of
+   the object returned by :meth:`dict.keys`.
+
+
+.. c:function:: int PyDictKeys_Check(PyObject *op)
+
+   Return true if *op* is an instance of a dictionary keys view. This function
+   always succeeds.
+
+
+.. c:var:: PyTypeObject PyDictValues_Type
+
+   Type object for a view of dictionary values. In Python, this is the type of
+   the object returned by :meth:`dict.values`.
+
+
+.. c:function:: int PyDictValues_Check(PyObject *op)
+
+   Return true if *op* is an instance of a dictionary values view. This function
+   always succeeds.
+
+
+.. c:var:: PyTypeObject PyDictItems_Type
+
+   Type object for a view of dictionary items. In Python, this is the type of
+   the object returned by :meth:`dict.items`.
+
+
+.. c:function:: int PyDictItems_Check(PyObject *op)
+
+   Return true if *op* is an instance of a dictionary items view. This function
+   always succeeds.