Add PUT, PATCH, and DELETE to form method attribute

[theandrewbailey]

A while ago, I was looking at the delete comment buttons on my blog, and noticed the form's POST method, and realized that DELETE would be more semantically accurate. Then I learned that you can't have DELETE as a form method; you can only do that in ajax requests. A casual search about form method DELETE requests mentioned a lot of irrevelant (to me) issues and corner cases around cross origin requests, but almost nothing was said about the happy path of talking to the same server (what I would be doing).