Function editor reports wrong position for syntax errors

When saving a function fails due to a syntax error, the line number of the error as reported in the butter bar is wrong. It appears to be offset by 5 lines, presumably due to the magic header lines:

```JS
// @copy_properties true
// @set_prop verb = "whatever"
// @set_prop dobj = "any"
// @set_prop prep = "none"
// @set_prop iobj = "none"
```