History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on 64e5964e9f132a1a209dd85292a1671d9324cd5cc3786d094ab12d18c9377f1e. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 101,107:crates/backdrop/src/mark.rs.