bug#47837: Ftp in passive mode with a link-to-rfc action type

[Brad Knotwell]

I use:  Editor:      GNU Emacs 27.2 (build 1, x86_64-apple-darwin17.7.0, Carbon 
Version 158 AppKit 1561.6)

        Hyperbole:   7.1.3
        Sys Type:    x86_64-apple-darwin17.7.0
        OS Type:     darwin
        Window Sys:  mac
        News Reader: Gnus v5.13

Linking to an RFC won't work most people as active mode ftp will be
blocked.  While people could customize ange-ftp-passive-host-alist to
include ftp.ietf.org, I would suggest switching the access method to
https instead:

   https://www.ietf.org/rfc/rfc1918.txt

Thx.

--Brad