Remove role=button in Button

[Klustre]

Thanks a lot for your efforts on this Hunter! Svelte desperately needs a proper UI library and I'm looking forward using it in my projects.

I noticed role=button is used in the Button component which incorrectly tells screen readers that the link is a button, but it's merely displayed as a button. It doesn't have the same functionality.

See mdn and this picocss issue.

When omitting the href param it actually is a button which should make role=button unnecessary.

[huntabyte]

Thanks for this! This specific repo is still very young and experimental!