s/get-tree-head-to-cosign/get-next-tree-head/
    s/get-tree-head-cosigned/get-tree-head/
    s/tree_size/size/
    s/inclusion_path/node_hash/
    s/consistency_path/node_hash/

Proposed in
https://git.glasklar.is/sigsum/project/documentation/-/blob/main/proposals/2022-07-api-renaming.md.