Simple Enhancement. Add missing return statements in ftplib documentation. (GH-25968) (#25969)

(cherry picked from commit b32c8e97951db46484ba3b646b988bcdc4062199)

Co-authored-by: Senthil Kumaran <senthil@uthcode.com>

Co-authored-by: Senthil Kumaran <senthil@uthcode.com>
diff --git a/Doc/library/ftplib.rst b/Doc/library/ftplib.rst
index f4d4cdf..3a9165a 100644
--- a/Doc/library/ftplib.rst
+++ b/Doc/library/ftplib.rst
@@ -28,6 +28,7 @@
    >>> ftp.login()                     # user anonymous, passwd anonymous@
    '230 Login successful.'
    >>> ftp.cwd('debian')               # change into "debian" directory
+   '250 Directory successfully changed.'
    >>> ftp.retrlines('LIST')           # list directory contents
    -rw-rw-r--    1 1176     1176         1063 Jun 15 10:18 README
    ...
@@ -39,6 +40,7 @@
    >>>     ftp.retrbinary('RETR README', fp.write)
    '226 Transfer complete.'
    >>> ftp.quit()
+   '221 Goodbye.'
 
 
 The module defines the following items: