This plugin for remarkable allows you to add custom double bracket syntaxes to your remarkable parser.
For example:
var rm_brackets = require("remarkable-brackets");
var Remarkable = require("remarkable");
var remarkable = new Remarkable("full", {html: true, breaks: true})
remarkable.use(rm_brackets({name: "cloze", :opener "{", closer: "}"}));
Now you can use syntax like:
This is my {{new syntax}}.