Fix missing semicolons at generated struct fields in .d.ts

[rhysd]

I had Rust+Wasm tutorial (Thank you for nice tutorial BTW!) and found that generated TypeScript type definition was wrong.

Rust:

#[wasm_bindgen]
pub struct Universe {
    pub width: u32,
    pub height: u32,
    // ...
}

Generated .d.ts

export class Universe {
free(): void;
width: number
height: number

// ...
}

TypeScript class property requires semicolon at the end. https://www.typescriptlang.org/docs/handbook/classes.html

So I expected

export class Universe {
free(): void;
width: number;
height: number;

// ...
}

I fixed the issue by this PR.

I confirmed it fixes the issue by manually building wasm-bindgen cli and running it in my local project. But I did not add any test for this change because I could not find any tests for TypeScript .d.ts generation.

[alexcrichton]

Oops, thanks for this!