+1 to the support, this is a brilliant plugin! Couple of quick queries:
Is there a reason for @@ rather than just @?
Would be great if it could be accessed in the WYSIWYG editor. I use this mode most of the time now and my muscle memory already goes straight to '@@'... only to discover nothing happens 
Thanks again for taking the time on this plugin.
I thought one @ is used in email addresses, 2 probably never occur anywhere.
There's no support for plugins targeting the WYSIWYG editor at present (and no plans to add it as far as I know). The best that can be done is add a menu item/hotkey that would bring up a search dialog from where you can search for a note and have a link to that note inserted. Arguably this can be even more powerful that the current plugin where you can only search by note title. I may add it at some points but no ETA.
There is only one small problem, I have with the @@:
It does not work with a sign directly afterwards, e.g.:
If I want to put the Link in brackets, then the opening '(' is directly followed by an automatic closing ')'. And if I then want to use @@ it does not do its magic...(@@).
Could that somehow be fixed?