[TS] Code generation error

The following `derw` code defines a lambda of type `string -> string`.

```derw
main: string -> string
main = \name -> `Hello ${name}`
```

Running `derw compile` on this results in the following output:

```ts
function main(_0: string): string {
return function(name: any) {
return `Hello ${name}`;
};
}
```

which declares that main is a `string -> string` but in reality, `main: string -> any -> string` as is evident from the code.

However, using the regular function notation like so

```derw
main: string -> string
main name = `Hello ${name}`
```

fixes the problem:

```ts
function main(name: string): string {
return `Hello ${name}`;
}
```

Run the provided derw compile example and compare the lambda output with the regular function output. Trace the TypeScript code-generation path for typed lambdas; done means the generated function preserves the declared string-to-string type instead of introducing any.

Written by the indexing model from the issue text.