Revert "Re-phrased titles for diff and history pages"

Revert "Re-phrased titles for diff and history pages"

This reverts commit af988eccc8981467c8bf4b639b47f673ab8d59e6

- It is inconsistent with all other actions and special pages (move page, edit page, delete page, What links here, search, ...)
- The exact spelling is (whether or not to uppercase the suffix, how to use quotation) is under heavy discussion on en.wikipedia (although it is not deployed yet, someone took the liberty to make the same change locally to see how people react, see also next point)
- Whether or not this actually improves tabbed browsing is imho highly doubtful. I consider myself to be an active vandal fighter and when working with fixing up vandals' contributions I sometimes have 50 tabs open. Some are diffs some are history etc. Knowing the action is imho more important than the page title. But having said that, both have their fair points (Either you can have 3 tabs like "Foo:Bar .." and not know which is what action. Or have 3 tabs like "Difference be.." and not know which is for which page). Imho the breadcrumb path "Action < Page < Site" makes more sense.
- See also discussion on the original gerrit change

Overal revert summary: Has issues, until resolved and if still relevant after that, for now reverting to status quo.