gh-98561: Fix a typo in typing (GH-98562)

Doc/library/typing.rst

@@ -319,7 +319,7 @@ single type parameter ``T`` . This also makes ``T`` valid as a type within the
 class body.
 
 The :class:`Generic` base class defines :meth:`~object.__class_getitem__` so
-that ``LoggedVar[t]`` is valid as a type::
+that ``LoggedVar[T]`` is valid as a type::
 
    from collections.abc import Iterable