ftplib: update connect() docstring by mentioning 'timeout' argument

Lib/ftplib.py

@@ -134,6 +134,7 @@ class FTP:
         '''Connect to host.  Arguments are:
          - host: hostname to connect to (string, default previous host)
          - port: port to connect to (integer, default previous port)
+         - timeout: the timeout to set against the ftp socket(s)
          - source_address: a 2-tuple (host, port) for the socket to bind
            to as its source address before connecting.
         '''