bpo-32284: Fix documentation of BinaryIO and TextIO (#4832)

diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index d28a5d548431ef329479cbd75919ec55b0c12e1a..9c4777ac2fe5803c9cf1c4e13a9ea6ff35f68715 100644 (file)
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -774,9 +774,9 @@ The module defines the following classes, functions and decorators:
 
    Wrapper namespace for I/O stream types.
 
-   This defines the generic type ``IO[AnyStr]`` and aliases ``TextIO``
-   and ``BinaryIO`` for respectively ``IO[str]`` and ``IO[bytes]``.
-   These represent the types of I/O streams such as returned by
+   This defines the generic type ``IO[AnyStr]`` and subclasses ``TextIO``
+   and ``BinaryIO``, deriving from ``IO[str]`` and ``IO[bytes]``,
+   respectively. These represent the types of I/O streams such as returned by
    :func:`open`.
 
    These types are also accessible directly as ``typing.IO``,