Unable to use brackets in string template

I wanted to do a generic log-error on htmx errors, and include a timestamp to make it easier to find in logs. However until #123 is fixed, I need to use the basic js date function. To get an Iso Timestamp it seemed easy to do something like this: `(new Date()).toISOString()` giving me the following code:

```html

```

However the (great) hyperscript parser seems to dislike the `(` inside a curly:

```
hyperscript errors were found on the following element:

Expected ')' but found 'Date'

${(new Date()).toISOString()}
```

Is this a known bug or should i do something completely different?