Changes touching this path

• a merge stops settling a tip whose tree the caller still owes on the next line, because the two sites that open-coded finalize plus materialize_tree now settle through SettleTree::Materialize, and converge's hand-written persist() is the settle tail its own write was spelled out beside, with the one of the three that no test in the crate ever entered now pinned (#1468) 15e33421 · 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.