templates as
       *   `_templateInfo` (a performance optimization to avoid deep template
       *   cloning)
       *
       * Note that the memoized template parsing process is destructive to the
       * template: attributes for bindings and declarative event listeners are
       * removed after being noted in notes, and any nested `<template>.content`
       * is removed and stored in notes as well.
       *
       * @param {HTMLTemplateElement} template Template to stamp
       * @return {DocumentFrag