fixed bug where all events had to have handlers in hooks

[jdpigeon]

I was trying to use the hooks option to set some logic today and discovered that the typing is wrong currently and requires handlers to be provided for ALL event types if using this option:

// ...
        hooks: {
          run: eventHandler,
        },
// Throwing error related to missing ""before:prepare", prepare, render, end", etc.
// ...

This type change allows the previous code to be valid

[jdpigeon]

Unlike most index signatures, I think this requires all instances of EventName to be present specifically because the index signature is an enum