Make the `HandlerBuilder` class a `CallableObject`

Make the `HandlerBuilder` class extend the `CallableObject` class.  
This will make it easier to use.

e.g.
```ts
const handler = new HandlerBuilder()
  .on(ValueError, () => { ... })
  .on(SyntaxError, () => { ... })
  .default(() => { ... });

// example 1
try { ... }
catch (error)
{
  handler(error);
}

// example 2
new Promise([...])
  .catch(handler);
```