update docs, catch promise errors

docs/template.md

@@ -45,7 +45,7 @@ You can use subtemplates as follows:
 ```html
 <template class="tmpl-head" src="heading.html" data-target="false"></template>
 <template class="main" data-template-header=".tmpl-head">
-  <%= head({title: "Page title"}) %>
+  <%= header({title: "Page title"}) %>
 </template>
 <script>
   $('.main').template()