XQuery 3.0 Function Annotations

Hi Phil,

I was wondering if it may be possible to support Function Annotations?

```xquery
declare
  %my-ns:my-local("my value")
  %xdmp:single-without-arguments
  %xdmp:four-data-types("string", true, false, 123, 123.456)
function local:process($var as xs:string)
{
  1 to 10
};
```

Regards,

Charles