API Documentation

As far as I can tell there is no easily accessible API documentation outside of the source code.

However, the typescript declaration file has most functions documented in addition to its types.

I suggest using `typedoc` to generate documentation. Users can do this themselves or this can be hosted online for free. An example: https://funkia.github.io/hareactive/

This command worked for me:

```
typedoc —out godot-ts-doc ./godot.d.ts —ignoreCompilerErrors —module commonjs —target es6 —includeDeclarations ./godot.d.ts
```

Additionally, I am available to help with documentation beyond this. This is a high-quality project and I would like to help it be as visible and accessible as possible.

Start by reviewing the TypeScript declaration file godot.d.ts and the provided typedoc command. Done means generating API documentation from the declarations and making the resulting documentation accessible to users, either through documented local generation or an online host.

Written by the indexing model from the issue text.