Mention svelte-french-toast in README

[kbrgl]

Thanks for making this awesome package—I use it in nearly every React project. Could I send a PR to add Svelte French Toast to the README?

I wanted something similar for a Svelte project but couldn’t find anything, so I ported React Hot Toast over to Svelte French Toast. I think it'll be helpful for people searching for an alternative like I was. Happy to send a quick PR if you think it's okay.

Thanks again!