Clarify that isatty is only guaranteed to return true for slave ends of

Yhg1s · Yhg1s · commit 12e1595e2820 · 2000-10-03T16:54:24.000Z
terminals, not the master end (though it does, on most systems.)
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
@@ -3468,7 +3468,7 @@ posix_fdopen(PyObject *self, PyObject *args)
 static char posix_isatty__doc__[] =
 "isatty(fd) -> Boolean\n\
 Return true if the file descriptor 'fd' is an open file descriptor\n\
-connected to a terminal.";
+connected to the slave end of a terminal.";
 
 static PyObject *
 posix_isatty(PyObject *self, PyObject *args)
