bpo-38244: [Documentation] Fix unreliable link to sever in ftplib.rst (#16319)

diff --git a/Doc/library/ftplib.rst b/Doc/library/ftplib.rst
index db02123..79a0286 100644
--- a/Doc/library/ftplib.rst
+++ b/Doc/library/ftplib.rst
@@ -22,7 +22,7 @@
 Here's a sample session using the :mod:`ftplib` module::
 
    >>> from ftplib import FTP
-   >>> ftp = FTP('ftp.debian.org')     # connect to host, default port
+   >>> ftp = FTP('ftp.us.debian.org')  # connect to host, default port
    >>> ftp.login()                     # user anonymous, passwd anonymous@
    '230 Login successful.'
    >>> ftp.cwd('debian')               # change into "debian" directory