Show full file changes for merge request (again)

Description

Show full file changes for merge request (again).

Proposal

The recent changes to improve Navigating files in merge request diff have removed the ability to glance at the entire list of file changes. I propose to make it possible to either show a full list at the top of the merge request (as before these recent changes) (in addition to the new sticky dropdown approach) or make it possible to toggle between the new sticky dropdown approach and the full list at the top.

Links / references

Documentation blurb

Overview

What is it? Why should someone use this feature? What is the underlying (business) problem? How do you use this feature?

Use cases

Who is this for? Provide one or more use cases.

Feature checklist

Make sure these are completed before closing the issue, with a link to the relevant commit.