Update the pty.openpty docs.

Author: gpshead

Doc/library/pty.rst

@@ -34,9 +34,12 @@ The :mod:`pty` module defines the following functions:
 
 .. function:: openpty()
 
-   Open a new pseudo-terminal pair, using :func:`os.openpty` if possible, or
-   emulation code for generic Unix systems. Return a pair of file descriptors
-   ``(master, slave)``, for the master and the slave end, respectively.
+   Open a new pseudo-terminal pair, this is an alias for :func:`os.openpty`.
+   Return a pair of file descriptors ``(master, slave)``, for the "master" and
+   the "slave" sides of the ``pty``.
+
+.. versionchanged:: 3.12
+   Emulation on legacy Unix systems without :func:`os.openpty` was removed.
 
 
 .. function:: spawn(argv[, master_read[, stdin_read]])