const t1: tmplConf = '<div>Hello</div>'
const t2: tmplConf = fetchHtml('./template.html') // Lazy loading
const t3: tmplConf = () => fetchHtml('./template.html') // Lazy loading
const t4: tmplConf = new JJHE(document.createElement('div')) // JJHE instance
const t5: tmplConf = document.createElement('div') // Raw HTMLElement
const t6: tmplConf = await fetchHtml('./template.html') // Eager loading
Configuration for the component's template. Can be an HTML string, a JJHE instance, a raw HTMLElement, or a Promise / factory that yields one of those.