[feature] Add title to diff view, move Style selection to top menu div

[jhedlund]

Describe the solution you'd like

I have some watchers that have similar and long URLs that makes it difficult to quickly discern which watch it is.

I would propose either:

1. Put the existing html link in the menu bar in an anchor tag with the title as the name of the link
2. Put the title above the link (so full link is still visible if that is desirable)

Secondly, I find myself changing the Styles periodically depending on which history I am looking at or what the changes actually work, but it's frustrating to scroll up every time to make those changes, so I would propose moving the Style selection to the menu header just beneath the link.

I am happy to create a PR for these (either combined or separately) if you think these ideas are good, just let me know.