Use button element instead of input for submit helper

Any special reason why not to ?

The source in question is this:

https://github.com/rails/rails/blob/master/actionview/lib/action_view/helpers/form_tag_helper.rb#L427-L431

Many people have talked before about the benefits of using instead of . There were some issues on IE6 but since it’s “officially dead” I think we can safely change to and let people opt back for on edge cases.

I’ve been using an initializer for this:

https://gist.github.com/haggen/11021520