marp: use sane defaults

.marp/engine.js

@@ -3,6 +3,14 @@
 const { Marp } = require('@marp-team/marp-core')
 
 module.exports = opts => {
+
+  opts.markdown = { ...opts.markdown }
+  opts.markdown.breaks = false
+  opts.markdown.html = true
+  opts.html = true
+
+  // console.log(opts)
+
   const marp = new Marp(opts)
 
   // Disable parsing fragmented list