fix the declare_and_export example

[timbod7]

Currently the example fails with:

$ cargo run --example declare_and_export
...
Error formatting typescript: Expected ';', got 'export' at file:///type_2.ts:1:31

  import { Bar } from './bar.ts'export type Foo = { bar: Bar;  }  ; 
                                ~~~~~~
$

With this tweak it runs successfully to completion.