Update README.md

[nicosabena]

Fixes options merging syntax, as confirm expects all the other options as root properties.

[haradakunihiko]

I'm actually passing these options as defined in YourDialog, so not using the spread operator works out fine. Initially, the idea was to make it easier to differentiate between optional and required parameters in the mix, but with TypeScript, we're managing that distinction through types. So, I'm leaning towards thinking this wrapper function might not even be necessary, maybe even considering removing it. Anyway, thanks for pointing it out!