[3.14] gh-141627: Fix BufferedRandom inheritance documentation (GH-141629) (GH-150802)

BufferedRandom does not inherit from BufferedReader and BufferedWriter
in the C implementation.
(cherry picked from commit 551bc2c)

Co-authored-by: Mohsin Mehmood <55545648+mohsinm-dev@users.noreply.github.com>

Author: miss-islington

Doc/library/io.rst

@@ -829,9 +829,9 @@ than raw I/O does.
 
 .. class:: BufferedRandom(raw, buffer_size=DEFAULT_BUFFER_SIZE)
 
-   A buffered binary stream providing higher-level access to a seekable
-   :class:`RawIOBase` raw binary stream.  It inherits from :class:`BufferedReader`
-   and :class:`BufferedWriter`.
+   A buffered binary stream implementing :class:`BufferedIOBase` interfaces
+   providing higher-level access to a seekable :class:`RawIOBase` raw binary
+   stream.
 
    The constructor creates a reader and writer for a seekable raw stream, given
    in the first argument.  If the *buffer_size* is omitted it defaults to