Out of date mustache example for client-side-templates extension in the docs.

[airblast-dev]

The linked jsbin in the docs is quite out of date, so I will focus on the full example on the doc page itself.

• The json from https://jsonplaceholder.typicode.com/todos/1 returns a UserId, and not a UserID. So in the result we get a blank string. Simply making the last character lowercase fixes this issue.
• Clicking the button on the full example will keep in some artifacts from the template. We end up with a bunch of "{% raw %}", and "{% endraw %}". Simply removing those from the template fixes the issue.