Update promise.wait to throw an error when timeout reached or interrupted

[chipsenkbeil]

Per the comment I made in our main org roam issue, I discovered that Promise.wait does not throw an error when the timeout is reached. Instead, it returns nil.

This can be a problem if you're returning OrgPromise<nil>, as it misleads the promise as succeeding when in reality it may have not completed yet.

This updates Promise.wait to check the return values from vim.wait to determine if a value should be returned or if an error should be thrown.

[chipsenkbeil]

Looks good, just some minor refactoring around the checks.

Good to go :)

[kristijanhusak]

Thanks!