History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on 27babfa165801e966a746a009b6f5cf8d610b3866e1200163b3ae02b9a8eb8d5. 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.