History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on a22e4aec2e28e7e116863dacacb175a7b7e495581073e1b757840b5ae33ec0b5. 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.