UI review/update on method/path dropdown

[lornajane]

As part of #1279 I noticed this feature for a request in the right hand bar:

I can't access it without a mouse, and now I've opened it, I'm not sure what it does! It should be focusable but can I edit this URL or something? Copy it? Probably we should update this description with a better explanation of what this does before we try to fix anything!

Looking at the source, it's <div> tags with events attached and more <div> and <span> inside. If users should be able to interact with it there should probably be links/buttons/inputs used instead.

Checking the Firefox Accessibility tools:

Clickable elements must be focusable and should have interactive semantics. Learn more

Also there's an unlabelled graphic (that down arrow polygon on the right hand side) that we could attach a label to while we're here.