Better types for custom elements

[Atulin]

I decided to add some more types to the custom element registration function, mainly around ensuring that the prop name array passed to it adheres to the actual props passed to the component.

Before commit, I ran denoify, as well as prettier and eslint.

Ideally, I'd like to eradicate any from the entire codebase, but... small steps. And maybe a fork proper, if proper typings are not something the project maintanier desires.

[yandeu]

Thanks for your PR. Some check have failed. I will have a look once I find a litte time.

[yandeu]

I'm very interested in better types, but I think it is difficult because of the flexibility of nano-jsx.

Unfortunately, the tests fail :(

There is no need for running denoify before commiting