but I cannot remember the right syntax

You have it spot on. They're all of the format [scheme://optional_identifier|optional_alt_text].

Linking syntax is available in What shortcuts can I use for linking to other information? in the PerlMonks FAQ (accessed via the "Need Help??" in the top right corner).

And I dont enjoy having to remember yet another HTML shorthand

Then don't use it. All we ask is that you don't link to a PerlMonks specific domain. (e.g. <a href="/?node_id=646560">here</a> would be fine.) People use various domains to read this site (www.perlmonk.org, perlmonk.org, www.perlmonks.com, perlmonks.com, www.perlmonks.net, perlmonks.net, etc). Following a link to a different domain causes the user to get logged out.

The advantage of [id://XXXXXX] is that it fetches the node title so you don't have to look it up yourself or use something lame like "here".

By the way, what you posted was invalid HTML. It's only safe to omit the quotes around attribute values when the value matches /^[a-zA-Z0-9-._:]*\z/.