Feature Request: Add Button "type" prop

[prashnts]

It'd be quite nice to have a type prop on the Button component. Currently, it renders as <button type="button" .../>.

In a form, if there is a <button type="submit", then the onSubmit event is fired if return key is pressed from an input field. This is a handy default behaviour which is worth keeping IMO.

I can make a PR adding a type prop to Button component and ButtonType (?) enum to implement this behaviour.

Thanks!

[giladgray]

Buttons most certainly already support the type prop--they support all HTML props--it's just not listed in the documentation.

@prashnts try it yourself! <Button type="submit" /> should work as expected.