Updated submit buttons on vendor and product pages to be inputs, rather than <a> tags, so enter will submit the form
Reverted <input> to an <a>, so tests pass, since the partial doesn't appear to be used in the UI
Edited <a> buttons to <button> buttons, to allow for keyboard-based submission of Devise forms
Changed some email_field form elements to text_field form elements, so they validate in-browser correctly now