It looks like these have required you to type in monograms/object names (not acted as typeaheads) since late 2013, when they were last touched (D7823). Their behavior doesn't seem to have changed, and still seems to work fine.

I'll convert "Repositories" to a typeahead in T8096. We don't have typeaheads for diffs, revisions or commits and I'm not sure it's useful to provide them. We could pop open the "Object Selector" dialog (used by, e.g., "Edit Differential Revisions") but this is a lot of work. A lower-effort compromise might be something like adding some placeholder text.