Changes touching this path

• re-pointing the working tree becomes one call that carries the #436 clobber guard with it, so the four bisect checkouts stop destroying an edit made while testing a midpoint, and no caller is left owing a guard that only a doc comment could name for it (#1414) 17abc3a0 · 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.