fix: typescript definitions broken

[bemisguided]

Checklist

• The new code additions passed the tests (npm test).
• The linter ran and found no issues (npm run-script lint).

Description

The TypeScript definitions were not working for me. I tried the following variations:

import * as inkjs from 'inkjs'

let story: inkjs.Story;

import { Story } from 'inkjs'

let story: Story;

In both cases I received the error: 'Story' refers to a value, but is being used as a type here. Did you mean 'typeof Story'?

I attempted typeof inkjs.Story and typeof Story but in both cases this caused TypeScript to not recognized any of the properties and methods of the Story class.

With the changes in this PR, both the above methods of importing work.