chore(type-checking): Cannot use only callback in run() without ts error

[plumpNation]

Addresses #706

[WilcoFiers]

Cool! Can you also add the scenario where there's no callback? If you don't use a callback, aXe will return a thenable.

[plumpNation]

Ok no worries. I have removed the optional params and locked it down with explicit overloads instead.

I have also added some types to make the overloads more readable.

[WilcoFiers]

Awesome. Thanks for the contribution @plumpNation Just a heads up, it'll be a few weeks before we can release this, since we're trying to put everything in its place to release aXe 3.0.