submission server instructions are confusing re whether to use TLS or STARTTLS

https://gitlab.torproject.org/tpo/tpa/team/-/wikis/howto/submission

The various incarnations of the setup instructions say to use port 587 with starttls in the bulleted list, and then below say that actually tls on 465 is preferred.

As someone unfamiliar with starttls, I was initially confused what this even meant, and thought that TLS and port 465 might be for a separate config option I wasn't seeing, rather than being mutually exclusive with starttls+587.

I think these ought to say to use TLS+465 in the bulleted lists for the client sections known to support that config (e.g. thunderbird), and either not mention the starttls+587 alternative, or just say it's also available but deprecated or whatever.

I would've just submitted a PR to take a stab at editing, but the workflow to fork a gitlab wiki and submit a PR isn't obvious from the UI, and I don't have the spoons to shave that yak at the moment :)