In a pull request, I can view either a single commit's diff, or the entire pull request's diff. e.g.
http://myUrl/projects/myProj/repos/myRepo/pull-requests/4/commits/hashTwo
or
http://myUrl/projects/myProj/repos/myRepo/pull-requests/4/diff
From the Compare screen, I can diff between any 2 commits I want, e.g.
http://myUrl/projects/myProj/repos/myRepo/compare/diff?targetBranch=hashOne&sourceBranch=hashTwo&targetRepoId=123
How can I, within a pull request, view the diff between arbitrary commits (both of which would be in that pull request)?