Changes touching this path

• loot diff and loot cat stop giving two answers about one embargoed path, because the four-rung absence ladder cat.rs already had moved into the delta seam and both renderers now match on it instead of each re-deriving burned-vs-sealed — and beside it an option group stops claiming the positionals of a leaf that never declared an arity, which is what would have turned `loot diff HEAD~1 HEAD` into a pathspec of its own selectors (#1551) 2248a1f4 · dbf3dbe6…

Renames are not followed. loot's tree maps a path to an address, so a rename is a delete and an add. This list is the history of the name, not of the bytes.