pythongh-144493: Improve error message in _overlapped.BindLocal() (python#144495)

Replace a confusing error message with one that actually explains what the error is in `_overlapped.BindLocal()`.

Fixes: python#144493

Author: dlech

Misc/NEWS.d/next/Library/2026-02-05-17-15-31.gh-issue-144493.XuxwVu.rst

@@ -0,0 +1 @@
+Improve an exception error message in ``_overlapped.BindLocal()`` that is raised when :meth:`asyncio.loop.sock_connect` is called on a :class:`asyncio.ProactorEventLoop` with a socket that has an invalid address family.

Modules/overlapped.c

@@ -559,7 +559,7 @@ _overlapped_BindLocal_impl(PyObject *module, HANDLE Socket, int Family)
         ret = bind((SOCKET)Socket, (SOCKADDR*)&addr, sizeof(addr))
                 != SOCKET_ERROR;
     } else {
-        PyErr_SetString(PyExc_ValueError, "expected tuple of length 2 or 4");
+        PyErr_SetString(PyExc_ValueError, "Only AF_INET and AF_INET6 families are supported");
         return NULL;
     }