[TypeScript] Async type signature always returns any

[leononame]

Description

Async does not generate correct type signature.

Repro code

REPL

Expected and actual results

It should have some type signature like export const doAsync: Async<string> instead of any, and ideally should be awaitable as well from typescript without giving errors.

Related information

• Fable version: dotnet fable --version
• Operating system